<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:6481c506-9da0-45ce-a350-4ccf0770986f,g:5fb1ee37-ff73-4ceb-b179-e65bb4ddd180-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.sitime.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="simple" xlink:href="sitm-20251231.xsd#ConsolidatedStatementsofStockholdersEquity"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_081cd906-c783-4626-97fb-2e1cec4124c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_713b10e9-7756-4b32-86c3-872d7727eeda" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_081cd906-c783-4626-97fb-2e1cec4124c9" xlink:to="loc_us-gaap_StatementTable_713b10e9-7756-4b32-86c3-872d7727eeda" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_fbf6bf31-ae2c-4a56-b7bc-3516243e9684" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_713b10e9-7756-4b32-86c3-872d7727eeda" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_fbf6bf31-ae2c-4a56-b7bc-3516243e9684" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_fbf6bf31-ae2c-4a56-b7bc-3516243e9684_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_fbf6bf31-ae2c-4a56-b7bc-3516243e9684" xlink:to="loc_us-gaap_EquityComponentDomain_fbf6bf31-ae2c-4a56-b7bc-3516243e9684_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_cfbb3653-34ad-4cf8-b22c-b2d048c65c5a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_fbf6bf31-ae2c-4a56-b7bc-3516243e9684" xlink:to="loc_us-gaap_EquityComponentDomain_cfbb3653-34ad-4cf8-b22c-b2d048c65c5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_faea38de-9456-405b-a48f-ab2597912756" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_cfbb3653-34ad-4cf8-b22c-b2d048c65c5a" xlink:to="loc_us-gaap_CommonStockMember_faea38de-9456-405b-a48f-ab2597912756" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_07eed2d2-5588-44b0-8f22-8900b2a9a646" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_cfbb3653-34ad-4cf8-b22c-b2d048c65c5a" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_07eed2d2-5588-44b0-8f22-8900b2a9a646" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_07f17f2a-78d2-4a33-acc9-6c1618b188ae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_cfbb3653-34ad-4cf8-b22c-b2d048c65c5a" xlink:to="loc_us-gaap_RetainedEarningsMember_07f17f2a-78d2-4a33-acc9-6c1618b188ae" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_019bd9f1-357d-70fa-83a5-e56828e56ff2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_713b10e9-7756-4b32-86c3-872d7727eeda" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_019bd9f1-357d-70fa-83a5-e56828e56ff2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019bd9f1-357d-70fa-83a5-e56828e56ff2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_019bd9f1-357d-70fa-83a5-e56828e56ff2" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019bd9f1-357d-70fa-83a5-e56828e56ff2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019bd9f1-357d-7f87-9c3f-3598e3b761a1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_019bd9f1-357d-70fa-83a5-e56828e56ff2" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019bd9f1-357d-7f87-9c3f-3598e3b761a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_FollowOnPublicOfferingMember_019bd9f1-357d-7756-b5ad-8b5cc3748f62" xlink:href="sitm-20251231.xsd#sitm_FollowOnPublicOfferingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_019bd9f1-357d-7f87-9c3f-3598e3b761a1" xlink:to="loc_sitm_FollowOnPublicOfferingMember_019bd9f1-357d-7756-b5ad-8b5cc3748f62" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_7500be3d-5446-47e4-8a4c-26429c8c0e94" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_081cd906-c783-4626-97fb-2e1cec4124c9" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_7500be3d-5446-47e4-8a4c-26429c8c0e94" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_4ebb5926-738d-475c-9b8a-97748f6fa7cd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_7500be3d-5446-47e4-8a4c-26429c8c0e94" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_4ebb5926-738d-475c-9b8a-97748f6fa7cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_df9e6006-a4d4-4666-8d6c-54807b20599e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_7500be3d-5446-47e4-8a4c-26429c8c0e94" xlink:to="loc_us-gaap_StockholdersEquity_df9e6006-a4d4-4666-8d6c-54807b20599e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_2e79a6dc-cbaf-400a-8618-a0a8b7cde537" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_7500be3d-5446-47e4-8a4c-26429c8c0e94" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_2e79a6dc-cbaf-400a-8618-a0a8b7cde537" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_259c40da-1f1a-4f78-87c3-09df9ba8f553" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_7500be3d-5446-47e4-8a4c-26429c8c0e94" xlink:to="loc_us-gaap_NetIncomeLoss_259c40da-1f1a-4f78-87c3-09df9ba8f553" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_a2b418cd-b550-4cc5-9227-2c7db5b7a1d1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_7500be3d-5446-47e4-8a4c-26429c8c0e94" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_a2b418cd-b550-4cc5-9227-2c7db5b7a1d1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_77a0cfe9-e003-43db-8f5f-34c31580bfad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_7500be3d-5446-47e4-8a4c-26429c8c0e94" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_77a0cfe9-e003-43db-8f5f-34c31580bfad" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings_44d3ffac-d6b4-430f-a714-6d6f067e055e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_7500be3d-5446-47e4-8a4c-26429c8c0e94" xlink:to="loc_us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings_44d3ffac-d6b4-430f-a714-6d6f067e055e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockValueSharesIssuedNetOfTaxWithholdings_04f85a58-c86a-4b19-9a02-7f5e9609b242" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockValueSharesIssuedNetOfTaxWithholdings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_7500be3d-5446-47e4-8a4c-26429c8c0e94" xlink:to="loc_us-gaap_RestrictedStockValueSharesIssuedNetOfTaxWithholdings_04f85a58-c86a-4b19-9a02-7f5e9609b242" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_ede176e6-a19d-4a20-94fa-be01550b4547" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_33f0e6a3-34bd-40f0-8426-1e4aa74a0af8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesFairValueMeasurementsDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#TheCompanyandSummaryofSignificantAccountingPoliciesFairValueMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesFairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_sitm_SignificantAccountingPoliciesLineItems_167026ea-7c2b-4e54-bff4-dff529e731ae" xlink:href="sitm-20251231.xsd#sitm_SignificantAccountingPoliciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_SignificantAccountingPoliciesTable_24524ec9-e69a-43ff-84b6-639e9378371e" xlink:href="sitm-20251231.xsd#sitm_SignificantAccountingPoliciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_167026ea-7c2b-4e54-bff4-dff529e731ae" xlink:to="loc_sitm_SignificantAccountingPoliciesTable_24524ec9-e69a-43ff-84b6-639e9378371e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_92b0c1ae-50af-462d-85ae-1da08cb78287" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_sitm_SignificantAccountingPoliciesTable_24524ec9-e69a-43ff-84b6-639e9378371e" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_92b0c1ae-50af-462d-85ae-1da08cb78287" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_92b0c1ae-50af-462d-85ae-1da08cb78287_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_92b0c1ae-50af-462d-85ae-1da08cb78287" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_92b0c1ae-50af-462d-85ae-1da08cb78287_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_63e8a3cb-4e33-48d7-afeb-9402e0114ef3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_92b0c1ae-50af-462d-85ae-1da08cb78287" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_63e8a3cb-4e33-48d7-afeb-9402e0114ef3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_f604c982-bb7d-4085-b30f-b6110a9090e0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_63e8a3cb-4e33-48d7-afeb-9402e0114ef3" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_f604c982-bb7d-4085-b30f-b6110a9090e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_c859c38b-9357-4879-9c50-aee3a172260c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_sitm_SignificantAccountingPoliciesTable_24524ec9-e69a-43ff-84b6-639e9378371e" xlink:to="loc_srt_RangeAxis_c859c38b-9357-4879-9c50-aee3a172260c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c859c38b-9357-4879-9c50-aee3a172260c_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_c859c38b-9357-4879-9c50-aee3a172260c" xlink:to="loc_srt_RangeMember_c859c38b-9357-4879-9c50-aee3a172260c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_51f38565-ed86-4dc0-8c04-d6a18a4a0623" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_c859c38b-9357-4879-9c50-aee3a172260c" xlink:to="loc_srt_RangeMember_51f38565-ed86-4dc0-8c04-d6a18a4a0623" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_9611a6ea-6faf-4e89-bd33-94f57ba4b225" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_51f38565-ed86-4dc0-8c04-d6a18a4a0623" xlink:to="loc_srt_MinimumMember_9611a6ea-6faf-4e89-bd33-94f57ba4b225" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_d25aa140-2e7f-4bda-99eb-e74133d0b03f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_51f38565-ed86-4dc0-8c04-d6a18a4a0623" xlink:to="loc_srt_MaximumMember_d25aa140-2e7f-4bda-99eb-e74133d0b03f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_6cefca68-c6ef-4213-ae1c-641a21a08e1e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_sitm_SignificantAccountingPoliciesTable_24524ec9-e69a-43ff-84b6-639e9378371e" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_6cefca68-c6ef-4213-ae1c-641a21a08e1e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_6cefca68-c6ef-4213-ae1c-641a21a08e1e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_6cefca68-c6ef-4213-ae1c-641a21a08e1e" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_6cefca68-c6ef-4213-ae1c-641a21a08e1e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_4189a097-85f0-437f-a8a8-4b281ff1b7f2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_6cefca68-c6ef-4213-ae1c-641a21a08e1e" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_4189a097-85f0-437f-a8a8-4b281ff1b7f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputPriceVolatilityMember_ff69bebd-0b8b-492c-b2df-dbf8fcd1be36" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputPriceVolatilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_4189a097-85f0-437f-a8a8-4b281ff1b7f2" xlink:to="loc_us-gaap_MeasurementInputPriceVolatilityMember_ff69bebd-0b8b-492c-b2df-dbf8fcd1be36" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_062f6800-ab4b-4b9f-ba8c-309a003fe800" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_4189a097-85f0-437f-a8a8-4b281ff1b7f2" xlink:to="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_062f6800-ab4b-4b9f-ba8c-309a003fe800" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputExpectedTermMember_79e666e6-32da-45ca-ac1e-1762683a60c2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputExpectedTermMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_4189a097-85f0-437f-a8a8-4b281ff1b7f2" xlink:to="loc_us-gaap_MeasurementInputExpectedTermMember_79e666e6-32da-45ca-ac1e-1762683a60c2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsAtCarryingValue_8b1e8b91-b6b5-4f46-8419-15c4f28abc66" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MoneyMarketFundsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_167026ea-7c2b-4e54-bff4-dff529e731ae" xlink:to="loc_us-gaap_MoneyMarketFundsAtCarryingValue_8b1e8b91-b6b5-4f46-8419-15c4f28abc66" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_TreasuryBillsMaturityDate_9e5e8030-001e-417c-8345-0a6589addce9" xlink:href="sitm-20251231.xsd#sitm_TreasuryBillsMaturityDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_167026ea-7c2b-4e54-bff4-dff529e731ae" xlink:to="loc_sitm_TreasuryBillsMaturityDate_9e5e8030-001e-417c-8345-0a6589addce9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_7a06b857-375d-44aa-a66f-e9a4dc17ef42" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_167026ea-7c2b-4e54-bff4-dff529e731ae" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_7a06b857-375d-44aa-a66f-e9a4dc17ef42" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss_35dbafcd-e22c-4406-9290-f6726d4292b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_167026ea-7c2b-4e54-bff4-dff529e731ae" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss_35dbafcd-e22c-4406-9290-f6726d4292b9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_9fee2614-a8bc-4069-b2b1-56f2e9af0e2a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_167026ea-7c2b-4e54-bff4-dff529e731ae" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_9fee2614-a8bc-4069-b2b1-56f2e9af0e2a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_8899aa16-d174-4bdc-ad83-6dcaac58fc0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_167026ea-7c2b-4e54-bff4-dff529e731ae" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_8899aa16-d174-4bdc-ad83-6dcaac58fc0a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput_c3b39348-978c-4ff4-9aab-1ae499422c2e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_167026ea-7c2b-4e54-bff4-dff529e731ae" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput_c3b39348-978c-4ff4-9aab-1ae499422c2e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleListNotDisclosedFlag_7f4ae2f8-bff7-4f3b-a731-e062a75e0544" xlink:href="sitm-20251231.xsd#sitm_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleListNotDisclosedFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_167026ea-7c2b-4e54-bff4-dff529e731ae" xlink:to="loc_sitm_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleListNotDisclosedFlag_7f4ae2f8-bff7-4f3b-a731-e062a75e0544" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#TheCompanyandSummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_feaf52bc-00d0-4095-b90a-412d8739eb49" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_834fbfac-5080-4c41-a8f7-7eeb56865654" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_feaf52bc-00d0-4095-b90a-412d8739eb49" xlink:to="loc_us-gaap_ConcentrationRiskTable_834fbfac-5080-4c41-a8f7-7eeb56865654" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_86850418-c65d-4095-ad80-1d82d2b7ead6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_834fbfac-5080-4c41-a8f7-7eeb56865654" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_86850418-c65d-4095-ad80-1d82d2b7ead6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_86850418-c65d-4095-ad80-1d82d2b7ead6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_86850418-c65d-4095-ad80-1d82d2b7ead6" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_86850418-c65d-4095-ad80-1d82d2b7ead6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_fa775345-09e5-4e58-96aa-6db4443cb93f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_86850418-c65d-4095-ad80-1d82d2b7ead6" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_fa775345-09e5-4e58-96aa-6db4443cb93f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_ec6bd3da-8e53-486d-ae1f-5395c9d675cd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_fa775345-09e5-4e58-96aa-6db4443cb93f" xlink:to="loc_us-gaap_SalesRevenueNetMember_ec6bd3da-8e53-486d-ae1f-5395c9d675cd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_bb180364-b9b3-425a-a042-1837fd2bcd16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_834fbfac-5080-4c41-a8f7-7eeb56865654" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_bb180364-b9b3-425a-a042-1837fd2bcd16" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_bb180364-b9b3-425a-a042-1837fd2bcd16_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_bb180364-b9b3-425a-a042-1837fd2bcd16" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_bb180364-b9b3-425a-a042-1837fd2bcd16_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_bdd326af-e9cd-4480-a8fb-53c29df50d28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_bb180364-b9b3-425a-a042-1837fd2bcd16" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_bdd326af-e9cd-4480-a8fb-53c29df50d28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditConcentrationRiskMember_c06abf77-f5b9-48db-ab11-2c2b56fc1645" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_bdd326af-e9cd-4480-a8fb-53c29df50d28" xlink:to="loc_us-gaap_CreditConcentrationRiskMember_c06abf77-f5b9-48db-ab11-2c2b56fc1645" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_NumberOfDistributorsRepresentingMoreThanTenPercentOfRevenue_2b1f4587-4a92-4185-b1a0-0b46a21810a6" xlink:href="sitm-20251231.xsd#sitm_NumberOfDistributorsRepresentingMoreThanTenPercentOfRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_feaf52bc-00d0-4095-b90a-412d8739eb49" xlink:to="loc_sitm_NumberOfDistributorsRepresentingMoreThanTenPercentOfRevenue_2b1f4587-4a92-4185-b1a0-0b46a21810a6" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesScheduleofConcentrationofRiskbyRiskFactorDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#TheCompanyandSummaryofSignificantAccountingPoliciesScheduleofConcentrationofRiskbyRiskFactorDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesScheduleofConcentrationofRiskbyRiskFactorDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_5bf86a2d-89a7-4e6c-b206-7c5b579a36bb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_402488d8-c90e-42df-84f0-2d61735507a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_5bf86a2d-89a7-4e6c-b206-7c5b579a36bb" xlink:to="loc_us-gaap_ConcentrationRiskTable_402488d8-c90e-42df-84f0-2d61735507a0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_dd2f39c2-b450-488e-989b-b2632af884f3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_402488d8-c90e-42df-84f0-2d61735507a0" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_dd2f39c2-b450-488e-989b-b2632af884f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_dd2f39c2-b450-488e-989b-b2632af884f3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_dd2f39c2-b450-488e-989b-b2632af884f3" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_dd2f39c2-b450-488e-989b-b2632af884f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_4e2521cb-8143-42ec-ac51-62f7e1839f25" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_dd2f39c2-b450-488e-989b-b2632af884f3" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_4e2521cb-8143-42ec-ac51-62f7e1839f25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_178140d3-e9fe-4b07-a223-6a0153f628e9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_4e2521cb-8143-42ec-ac51-62f7e1839f25" xlink:to="loc_us-gaap_SalesRevenueNetMember_178140d3-e9fe-4b07-a223-6a0153f628e9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_7ee6fc90-a76c-4370-ab13-b73be32e26e9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_4e2521cb-8143-42ec-ac51-62f7e1839f25" xlink:to="loc_us-gaap_AccountsReceivableMember_7ee6fc90-a76c-4370-ab13-b73be32e26e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_498cba87-09ee-44e0-abbf-b4c865a9e152" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_402488d8-c90e-42df-84f0-2d61735507a0" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_498cba87-09ee-44e0-abbf-b4c865a9e152" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_498cba87-09ee-44e0-abbf-b4c865a9e152_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_498cba87-09ee-44e0-abbf-b4c865a9e152" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_498cba87-09ee-44e0-abbf-b4c865a9e152_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_f7b281f6-1bdd-4238-913b-5e91a7d757d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_498cba87-09ee-44e0-abbf-b4c865a9e152" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_f7b281f6-1bdd-4238-913b-5e91a7d757d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_0dd9ee18-54ff-486e-86f4-021fda548101" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_f7b281f6-1bdd-4238-913b-5e91a7d757d9" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_0dd9ee18-54ff-486e-86f4-021fda548101" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_6e683db0-6f5a-451d-957e-43ee0a0aa713" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_402488d8-c90e-42df-84f0-2d61735507a0" xlink:to="loc_srt_MajorCustomersAxis_6e683db0-6f5a-451d-957e-43ee0a0aa713" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_6e683db0-6f5a-451d-957e-43ee0a0aa713_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_6e683db0-6f5a-451d-957e-43ee0a0aa713" xlink:to="loc_srt_NameOfMajorCustomerDomain_6e683db0-6f5a-451d-957e-43ee0a0aa713_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_22457d8a-155b-4ff0-94c2-9d43d96f651d" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_6e683db0-6f5a-451d-957e-43ee0a0aa713" xlink:to="loc_srt_NameOfMajorCustomerDomain_22457d8a-155b-4ff0-94c2-9d43d96f651d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_CustomerOneMember_c0bada58-7dd4-4856-970f-46236ee915b2" xlink:href="sitm-20251231.xsd#sitm_CustomerOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_22457d8a-155b-4ff0-94c2-9d43d96f651d" xlink:to="loc_sitm_CustomerOneMember_c0bada58-7dd4-4856-970f-46236ee915b2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_CustomerTwoMember_e893b21e-0bc6-4cd9-aa50-157725d0eff4" xlink:href="sitm-20251231.xsd#sitm_CustomerTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_22457d8a-155b-4ff0-94c2-9d43d96f651d" xlink:to="loc_sitm_CustomerTwoMember_e893b21e-0bc6-4cd9-aa50-157725d0eff4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_CustomerThreeMember_dd3bec02-0b39-4081-8f03-c3b4143cddbf" xlink:href="sitm-20251231.xsd#sitm_CustomerThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_22457d8a-155b-4ff0-94c2-9d43d96f651d" xlink:to="loc_sitm_CustomerThreeMember_dd3bec02-0b39-4081-8f03-c3b4143cddbf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_CustomerFourMember_6a62ac3f-49fb-482f-bd1a-829391769fe5" xlink:href="sitm-20251231.xsd#sitm_CustomerFourMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_22457d8a-155b-4ff0-94c2-9d43d96f651d" xlink:to="loc_sitm_CustomerFourMember_6a62ac3f-49fb-482f-bd1a-829391769fe5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_85c680e3-11ce-4dc8-865e-e8b1120df78b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_5bf86a2d-89a7-4e6c-b206-7c5b579a36bb" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_85c680e3-11ce-4dc8-865e-e8b1120df78b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesScheduleofEstimatedUsefulLivesofthePropertyPlantandEquipmentDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#TheCompanyandSummaryofSignificantAccountingPoliciesScheduleofEstimatedUsefulLivesofthePropertyPlantandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesScheduleofEstimatedUsefulLivesofthePropertyPlantandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_sitm_SignificantAccountingPoliciesLineItems_23fc72f1-8c10-4d83-9016-b2079da2f6de" xlink:href="sitm-20251231.xsd#sitm_SignificantAccountingPoliciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_SignificantAccountingPoliciesTable_d254df7b-60cf-46bf-a70c-02b21c0e6483" xlink:href="sitm-20251231.xsd#sitm_SignificantAccountingPoliciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_23fc72f1-8c10-4d83-9016-b2079da2f6de" xlink:to="loc_sitm_SignificantAccountingPoliciesTable_d254df7b-60cf-46bf-a70c-02b21c0e6483" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_838c9070-a87d-4e6d-87e1-195a44f2a16d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_sitm_SignificantAccountingPoliciesTable_d254df7b-60cf-46bf-a70c-02b21c0e6483" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_838c9070-a87d-4e6d-87e1-195a44f2a16d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_838c9070-a87d-4e6d-87e1-195a44f2a16d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_838c9070-a87d-4e6d-87e1-195a44f2a16d" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_838c9070-a87d-4e6d-87e1-195a44f2a16d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8318f082-c624-405a-a867-8eaa97d153f1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_838c9070-a87d-4e6d-87e1-195a44f2a16d" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8318f082-c624-405a-a867-8eaa97d153f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LabAndManufacturingEquipmentMember_7b95a24f-46a8-4bac-bda6-6085e068ea3d" xlink:href="sitm-20251231.xsd#sitm_LabAndManufacturingEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8318f082-c624-405a-a867-8eaa97d153f1" xlink:to="loc_sitm_LabAndManufacturingEquipmentMember_7b95a24f-46a8-4bac-bda6-6085e068ea3d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerEquipmentMember_2e568b51-7e48-4392-92e1-4fc07a3585ed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComputerEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8318f082-c624-405a-a867-8eaa97d153f1" xlink:to="loc_us-gaap_ComputerEquipmentMember_2e568b51-7e48-4392-92e1-4fc07a3585ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_927a023a-9099-4d19-9e9c-0c12ebfae308" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8318f082-c624-405a-a867-8eaa97d153f1" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_927a023a-9099-4d19-9e9c-0c12ebfae308" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_b8fe9650-9ef8-48fe-9b9a-ab930248204c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_sitm_SignificantAccountingPoliciesTable_d254df7b-60cf-46bf-a70c-02b21c0e6483" xlink:to="loc_srt_RangeAxis_b8fe9650-9ef8-48fe-9b9a-ab930248204c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_b8fe9650-9ef8-48fe-9b9a-ab930248204c_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_b8fe9650-9ef8-48fe-9b9a-ab930248204c" xlink:to="loc_srt_RangeMember_b8fe9650-9ef8-48fe-9b9a-ab930248204c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9ecb9196-fd42-4340-ac6e-d24e8065b296" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_b8fe9650-9ef8-48fe-9b9a-ab930248204c" xlink:to="loc_srt_RangeMember_9ecb9196-fd42-4340-ac6e-d24e8065b296" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_bbb9c6af-8fe8-4c27-8c85-87dfde0bbd3e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9ecb9196-fd42-4340-ac6e-d24e8065b296" xlink:to="loc_srt_MinimumMember_bbb9c6af-8fe8-4c27-8c85-87dfde0bbd3e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_245cc114-9d57-4722-a056-3732e76f2188" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_9ecb9196-fd42-4340-ac6e-d24e8065b296" xlink:to="loc_srt_MaximumMember_245cc114-9d57-4722-a056-3732e76f2188" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_49764255-1875-44e7-944e-417c008a80e7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_23fc72f1-8c10-4d83-9016-b2079da2f6de" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_49764255-1875-44e7-944e-417c008a80e7" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesIntangibleAssetsDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#TheCompanyandSummaryofSignificantAccountingPoliciesIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_sitm_SignificantAccountingPoliciesLineItems_55b2002f-8666-47a7-a93e-ef6d957c70c4" xlink:href="sitm-20251231.xsd#sitm_SignificantAccountingPoliciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_SignificantAccountingPoliciesTable_214b4f48-ce55-4ba7-83ca-c667c8a89842" xlink:href="sitm-20251231.xsd#sitm_SignificantAccountingPoliciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_55b2002f-8666-47a7-a93e-ef6d957c70c4" xlink:to="loc_sitm_SignificantAccountingPoliciesTable_214b4f48-ce55-4ba7-83ca-c667c8a89842" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_73d2f897-8f86-4c73-8ba2-e006ce2c98c8" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_sitm_SignificantAccountingPoliciesTable_214b4f48-ce55-4ba7-83ca-c667c8a89842" xlink:to="loc_srt_RangeAxis_73d2f897-8f86-4c73-8ba2-e006ce2c98c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_73d2f897-8f86-4c73-8ba2-e006ce2c98c8_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_73d2f897-8f86-4c73-8ba2-e006ce2c98c8" xlink:to="loc_srt_RangeMember_73d2f897-8f86-4c73-8ba2-e006ce2c98c8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_6d0a839f-387e-447e-ac91-6293a0d19d8e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_73d2f897-8f86-4c73-8ba2-e006ce2c98c8" xlink:to="loc_srt_RangeMember_6d0a839f-387e-447e-ac91-6293a0d19d8e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_62cf3ec0-d44c-4fd6-9773-a3401b7a9167" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_6d0a839f-387e-447e-ac91-6293a0d19d8e" xlink:to="loc_srt_MinimumMember_62cf3ec0-d44c-4fd6-9773-a3401b7a9167" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_8abecf53-4b45-4847-80ce-2bf8b1c96abc" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_6d0a839f-387e-447e-ac91-6293a0d19d8e" xlink:to="loc_srt_MaximumMember_8abecf53-4b45-4847-80ce-2bf8b1c96abc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b4c50f70-edd9-41cb-88f5-ea6766ccd897" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_sitm_SignificantAccountingPoliciesTable_214b4f48-ce55-4ba7-83ca-c667c8a89842" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b4c50f70-edd9-41cb-88f5-ea6766ccd897" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b4c50f70-edd9-41cb-88f5-ea6766ccd897_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b4c50f70-edd9-41cb-88f5-ea6766ccd897" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b4c50f70-edd9-41cb-88f5-ea6766ccd897_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ba4a74af-1af2-4f45-8b33-0be37a4bd101" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b4c50f70-edd9-41cb-88f5-ea6766ccd897" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ba4a74af-1af2-4f45-8b33-0be37a4bd101" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PurchasedIntangiblesMember_2e2ee00c-af0c-47cd-8c33-d2bfcfd058e9" xlink:href="sitm-20251231.xsd#sitm_PurchasedIntangiblesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ba4a74af-1af2-4f45-8b33-0be37a4bd101" xlink:to="loc_sitm_PurchasedIntangiblesMember_2e2ee00c-af0c-47cd-8c33-d2bfcfd058e9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_079906fc-3e0e-4955-90d1-d4f251b46fd3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_55b2002f-8666-47a7-a93e-ef6d957c70c4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_079906fc-3e0e-4955-90d1-d4f251b46fd3" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesRevenueRecognitionDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#TheCompanyandSummaryofSignificantAccountingPoliciesRevenueRecognitionDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/TheCompanyandSummaryofSignificantAccountingPoliciesRevenueRecognitionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_sitm_SignificantAccountingPoliciesLineItems_10c30c97-462e-4f44-a5bd-88742a44e1ea" xlink:href="sitm-20251231.xsd#sitm_SignificantAccountingPoliciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_SignificantAccountingPoliciesTable_c8ec7dfd-7d73-4783-9179-a0c15de25743" xlink:href="sitm-20251231.xsd#sitm_SignificantAccountingPoliciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_10c30c97-462e-4f44-a5bd-88742a44e1ea" xlink:to="loc_sitm_SignificantAccountingPoliciesTable_c8ec7dfd-7d73-4783-9179-a0c15de25743" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_5cd4edda-2ff0-4cb0-ae57-35df164f847a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_sitm_SignificantAccountingPoliciesTable_c8ec7dfd-7d73-4783-9179-a0c15de25743" xlink:to="loc_srt_RangeAxis_5cd4edda-2ff0-4cb0-ae57-35df164f847a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_5cd4edda-2ff0-4cb0-ae57-35df164f847a_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_5cd4edda-2ff0-4cb0-ae57-35df164f847a" xlink:to="loc_srt_RangeMember_5cd4edda-2ff0-4cb0-ae57-35df164f847a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_163d3932-ce87-4c3a-b723-d6e642b2a52c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_5cd4edda-2ff0-4cb0-ae57-35df164f847a" xlink:to="loc_srt_RangeMember_163d3932-ce87-4c3a-b723-d6e642b2a52c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_c2c72636-88b2-4d8b-93cd-8b4505ca2960" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_163d3932-ce87-4c3a-b723-d6e642b2a52c" xlink:to="loc_srt_MinimumMember_c2c72636-88b2-4d8b-93cd-8b4505ca2960" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_fe86a4cd-5ab4-4d06-9482-b8229acb6f47" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_163d3932-ce87-4c3a-b723-d6e642b2a52c" xlink:to="loc_srt_MaximumMember_fe86a4cd-5ab4-4d06-9482-b8229acb6f47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_RevenueRecognizedPaymentTerms_ee1334b0-7bb8-4c01-bb68-496f86295977" xlink:href="sitm-20251231.xsd#sitm_RevenueRecognizedPaymentTerms"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_10c30c97-462e-4f44-a5bd-88742a44e1ea" xlink:to="loc_sitm_RevenueRecognizedPaymentTerms_ee1334b0-7bb8-4c01-bb68-496f86295977" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_RevenueRecognizedAmortizationPeriodTerm_93080370-65ca-4eaa-b7b8-f4669ff05ff0" xlink:href="sitm-20251231.xsd#sitm_RevenueRecognizedAmortizationPeriodTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_SignificantAccountingPoliciesLineItems_10c30c97-462e-4f44-a5bd-88742a44e1ea" xlink:to="loc_sitm_RevenueRecognizedAmortizationPeriodTerm_93080370-65ca-4eaa-b7b8-f4669ff05ff0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/AcquisitionsScheduleofAcquisitionDateFairValueofthePurchaseConsiderationDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#AcquisitionsScheduleofAcquisitionDateFairValueofthePurchaseConsiderationDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/AcquisitionsScheduleofAcquisitionDateFairValueofthePurchaseConsiderationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_97f89fec-3f3c-4310-803e-410173268ae8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9860108c-ca5a-4033-9176-916b22916788" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_97f89fec-3f3c-4310-803e-410173268ae8" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9860108c-ca5a-4033-9176-916b22916788" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_ef1e4b7f-dc90-4d2f-970c-94b8298fc058" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9860108c-ca5a-4033-9176-916b22916788" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_ef1e4b7f-dc90-4d2f-970c-94b8298fc058" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ef1e4b7f-dc90-4d2f-970c-94b8298fc058_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_ef1e4b7f-dc90-4d2f-970c-94b8298fc058" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ef1e4b7f-dc90-4d2f-970c-94b8298fc058_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_881308e3-4ea7-437a-87c2-97430abb70b8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_ef1e4b7f-dc90-4d2f-970c-94b8298fc058" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_881308e3-4ea7-437a-87c2-97430abb70b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AuraMember_208a67e5-03df-4866-a3ce-3692fd8222c7" xlink:href="sitm-20251231.xsd#sitm_AuraMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_881308e3-4ea7-437a-87c2-97430abb70b8" xlink:to="loc_sitm_AuraMember_208a67e5-03df-4866-a3ce-3692fd8222c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_FairValueOfPaymentsToAcquireBusinessesGross_b388a0b6-f281-4b07-a48c-0c02ef1729af" xlink:href="sitm-20251231.xsd#sitm_FairValueOfPaymentsToAcquireBusinessesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_97f89fec-3f3c-4310-803e-410173268ae8" xlink:to="loc_sitm_FairValueOfPaymentsToAcquireBusinessesGross_b388a0b6-f281-4b07-a48c-0c02ef1729af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred_405fc203-8d83-4d48-8956-d730d16316f0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_97f89fec-3f3c-4310-803e-410173268ae8" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred_405fc203-8d83-4d48-8956-d730d16316f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_BusinessCombinationConsiderationTransferredSupplyAgreementSettlement_9cbd4aec-5dc7-4ebf-99a1-e68dd3856525" xlink:href="sitm-20251231.xsd#sitm_BusinessCombinationConsiderationTransferredSupplyAgreementSettlement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_97f89fec-3f3c-4310-803e-410173268ae8" xlink:to="loc_sitm_BusinessCombinationConsiderationTransferredSupplyAgreementSettlement_9cbd4aec-5dc7-4ebf-99a1-e68dd3856525" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_e65a79d7-198b-41c1-9bb7-9d762c3b3983" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_97f89fec-3f3c-4310-803e-410173268ae8" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_e65a79d7-198b-41c1-9bb7-9d762c3b3983" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/AcquisitionsScheduleofAssetsAcquiredDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#AcquisitionsScheduleofAssetsAcquiredDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/AcquisitionsScheduleofAssetsAcquiredDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_d1181299-c3e2-4b5e-ba86-ffbe6df676b5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_74d70b16-6a93-4262-a9ba-a3b2fc518127" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d1181299-c3e2-4b5e-ba86-ffbe6df676b5" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_74d70b16-6a93-4262-a9ba-a3b2fc518127" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_f42b52c6-0a18-45b1-bd33-659a219efaa8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_74d70b16-6a93-4262-a9ba-a3b2fc518127" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_f42b52c6-0a18-45b1-bd33-659a219efaa8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f42b52c6-0a18-45b1-bd33-659a219efaa8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_f42b52c6-0a18-45b1-bd33-659a219efaa8" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f42b52c6-0a18-45b1-bd33-659a219efaa8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_89bb66ac-94ec-45bf-bc94-894eb3924b96" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_f42b52c6-0a18-45b1-bd33-659a219efaa8" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_89bb66ac-94ec-45bf-bc94-894eb3924b96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AuraMember_e11f40bf-7156-4fe4-9765-5ca0925d64bb" xlink:href="sitm-20251231.xsd#sitm_AuraMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_89bb66ac-94ec-45bf-bc94-894eb3924b96" xlink:to="loc_sitm_AuraMember_e11f40bf-7156-4fe4-9765-5ca0925d64bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a0a5866d-fda4-4ea8-b085-938d28284413" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_74d70b16-6a93-4262-a9ba-a3b2fc518127" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a0a5866d-fda4-4ea8-b085-938d28284413" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a0a5866d-fda4-4ea8-b085-938d28284413_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a0a5866d-fda4-4ea8-b085-938d28284413" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a0a5866d-fda4-4ea8-b085-938d28284413_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d52d432a-55cc-428e-8ba6-69f3f2e23ed3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a0a5866d-fda4-4ea8-b085-938d28284413" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d52d432a-55cc-428e-8ba6-69f3f2e23ed3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_f0ae8bc5-9d78-42fb-b27a-eb75ca9ddd3d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d52d432a-55cc-428e-8ba6-69f3f2e23ed3" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_f0ae8bc5-9d78-42fb-b27a-eb75ca9ddd3d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerContractsMember_dcd4b7f0-1447-46cf-9eb0-3967395c3747" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d52d432a-55cc-428e-8ba6-69f3f2e23ed3" xlink:to="loc_us-gaap_CustomerContractsMember_dcd4b7f0-1447-46cf-9eb0-3967395c3747" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_4ba6771c-83cd-4ddb-9caf-fdca02d48791" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_74d70b16-6a93-4262-a9ba-a3b2fc518127" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_4ba6771c-83cd-4ddb-9caf-fdca02d48791" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_4ba6771c-83cd-4ddb-9caf-fdca02d48791_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_4ba6771c-83cd-4ddb-9caf-fdca02d48791" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_4ba6771c-83cd-4ddb-9caf-fdca02d48791_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_92afc68c-f910-4d25-b542-9968cbcf318d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_4ba6771c-83cd-4ddb-9caf-fdca02d48791" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_92afc68c-f910-4d25-b542-9968cbcf318d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InProcessResearchAndDevelopmentMember_d524ed7a-520c-4262-b1d9-1486bf2d7849" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InProcessResearchAndDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_92afc68c-f910-4d25-b542-9968cbcf318d" xlink:to="loc_us-gaap_InProcessResearchAndDevelopmentMember_d524ed7a-520c-4262-b1d9-1486bf2d7849" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_b89ff040-b45f-47e0-ad5c-655669766a6a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_74d70b16-6a93-4262-a9ba-a3b2fc518127" xlink:to="loc_srt_RangeAxis_b89ff040-b45f-47e0-ad5c-655669766a6a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_b89ff040-b45f-47e0-ad5c-655669766a6a_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_b89ff040-b45f-47e0-ad5c-655669766a6a" xlink:to="loc_srt_RangeMember_b89ff040-b45f-47e0-ad5c-655669766a6a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_0673d1a2-4283-40e4-aa0f-beac62cb71b1" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_b89ff040-b45f-47e0-ad5c-655669766a6a" xlink:to="loc_srt_RangeMember_0673d1a2-4283-40e4-aa0f-beac62cb71b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_7a1b13cb-d2bb-4d62-a26e-c53a8037b703" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_0673d1a2-4283-40e4-aa0f-beac62cb71b1" xlink:to="loc_srt_MinimumMember_7a1b13cb-d2bb-4d62-a26e-c53a8037b703" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_a1f5f67c-7c56-408a-a2ec-033b98acd59d" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_0673d1a2-4283-40e4-aa0f-beac62cb71b1" xlink:to="loc_srt_MaximumMember_a1f5f67c-7c56-408a-a2ec-033b98acd59d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_af0165c3-4fc8-41db-a7f0-4e456c763b97" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d1181299-c3e2-4b5e-ba86-ffbe6df676b5" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_af0165c3-4fc8-41db-a7f0-4e456c763b97" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_15727902-c616-4309-93f2-38b74d7d6b2f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d1181299-c3e2-4b5e-ba86-ffbe6df676b5" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_15727902-c616-4309-93f2-38b74d7d6b2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_5f798e1a-f1a2-4a8d-8ef2-5af3974eddfd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d1181299-c3e2-4b5e-ba86-ffbe6df676b5" xlink:to="loc_us-gaap_Goodwill_5f798e1a-f1a2-4a8d-8ef2-5af3974eddfd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_245671c7-0f22-420f-84b8-76f7cf150c21" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d1181299-c3e2-4b5e-ba86-ffbe6df676b5" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_245671c7-0f22-420f-84b8-76f7cf150c21" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_13dfa1ad-6302-4f0d-a240-31b17353f3ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_d1181299-c3e2-4b5e-ba86-ffbe6df676b5" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_13dfa1ad-6302-4f0d-a240-31b17353f3ab" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/BalanceSheetsComponentsScheduleofPropertyandEquipmentNetDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#BalanceSheetsComponentsScheduleofPropertyandEquipmentNetDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/BalanceSheetsComponentsScheduleofPropertyandEquipmentNetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_579b021a-e97d-4420-b157-8ef0e324895a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_04d87a79-8cce-44cb-8361-6b32361f3689" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_579b021a-e97d-4420-b157-8ef0e324895a" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_04d87a79-8cce-44cb-8361-6b32361f3689" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_153a13a5-0292-42b4-8b0f-305746e3c0dc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_04d87a79-8cce-44cb-8361-6b32361f3689" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_153a13a5-0292-42b4-8b0f-305746e3c0dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_153a13a5-0292-42b4-8b0f-305746e3c0dc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_153a13a5-0292-42b4-8b0f-305746e3c0dc" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_153a13a5-0292-42b4-8b0f-305746e3c0dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8153eef7-7623-4a42-aa1d-4d1fabe62a95" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_153a13a5-0292-42b4-8b0f-305746e3c0dc" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8153eef7-7623-4a42-aa1d-4d1fabe62a95" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LabAndManufacturingEquipmentMember_e29bfc7d-5f1f-470b-88bc-38f65dc25e3f" xlink:href="sitm-20251231.xsd#sitm_LabAndManufacturingEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8153eef7-7623-4a42-aa1d-4d1fabe62a95" xlink:to="loc_sitm_LabAndManufacturingEquipmentMember_e29bfc7d-5f1f-470b-88bc-38f65dc25e3f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerEquipmentMember_7e13ed1f-4596-4fad-953a-8786d430822b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComputerEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8153eef7-7623-4a42-aa1d-4d1fabe62a95" xlink:to="loc_us-gaap_ComputerEquipmentMember_7e13ed1f-4596-4fad-953a-8786d430822b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_b495d97e-2230-49f3-957c-65581119127f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8153eef7-7623-4a42-aa1d-4d1fabe62a95" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_b495d97e-2230-49f3-957c-65581119127f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_ebc2cc5d-5297-4be4-beeb-5ed1af2e790b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8153eef7-7623-4a42-aa1d-4d1fabe62a95" xlink:to="loc_us-gaap_ConstructionInProgressMember_ebc2cc5d-5297-4be4-beeb-5ed1af2e790b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_c47d62f7-0c51-4973-b820-ee98c231a889" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8153eef7-7623-4a42-aa1d-4d1fabe62a95" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_c47d62f7-0c51-4973-b820-ee98c231a889" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_b8d223f7-d6c3-4043-a2a7-23671df2925a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_579b021a-e97d-4420-b157-8ef0e324895a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_b8d223f7-d6c3-4043-a2a7-23671df2925a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_81fd3b37-bf13-471d-8d3a-39b7358ae276" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_579b021a-e97d-4420-b157-8ef0e324895a" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_81fd3b37-bf13-471d-8d3a-39b7358ae276" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_4619dedd-d36b-45de-a4ee-0fb12fd0373f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_579b021a-e97d-4420-b157-8ef0e324895a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_4619dedd-d36b-45de-a4ee-0fb12fd0373f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/BalanceSheetsComponentsScheduleofIntangibleAssetsNetDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#BalanceSheetsComponentsScheduleofIntangibleAssetsNetDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/BalanceSheetsComponentsScheduleofIntangibleAssetsNetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_d32a03a6-1d8e-48c9-971a-ae527001dbc4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_09a81003-6501-496c-9503-da8b224bd73f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_d32a03a6-1d8e-48c9-971a-ae527001dbc4" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_09a81003-6501-496c-9503-da8b224bd73f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3cbb222c-55e2-45a2-96df-a9d7264f079b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_09a81003-6501-496c-9503-da8b224bd73f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3cbb222c-55e2-45a2-96df-a9d7264f079b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3cbb222c-55e2-45a2-96df-a9d7264f079b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3cbb222c-55e2-45a2-96df-a9d7264f079b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3cbb222c-55e2-45a2-96df-a9d7264f079b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_dfe38404-3184-444f-91ec-b73ca7a38c5b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_3cbb222c-55e2-45a2-96df-a9d7264f079b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_dfe38404-3184-444f-91ec-b73ca7a38c5b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_e4285f30-6b47-46a4-88ab-4bdd889a0937" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_dfe38404-3184-444f-91ec-b73ca7a38c5b" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_e4285f30-6b47-46a4-88ab-4bdd889a0937" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractBasedIntangibleAssetsMember_f465b3aa-bfca-4e5c-961d-772375f9e2d6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractBasedIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_dfe38404-3184-444f-91ec-b73ca7a38c5b" xlink:to="loc_us-gaap_ContractBasedIntangibleAssetsMember_f465b3aa-bfca-4e5c-961d-772375f9e2d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_InternalUseSoftwareMember_db9a6b8c-2a7c-4c64-91b0-2a8c8814f742" xlink:href="sitm-20251231.xsd#sitm_InternalUseSoftwareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_dfe38404-3184-444f-91ec-b73ca7a38c5b" xlink:to="loc_sitm_InternalUseSoftwareMember_db9a6b8c-2a7c-4c64-91b0-2a8c8814f742" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PurchasedSoftwareMember_001815f8-f873-4a0a-a047-a449a87857f6" xlink:href="sitm-20251231.xsd#sitm_PurchasedSoftwareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_dfe38404-3184-444f-91ec-b73ca7a38c5b" xlink:to="loc_sitm_PurchasedSoftwareMember_001815f8-f873-4a0a-a047-a449a87857f6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_6c6715f6-3f96-4442-b25a-e31c37b48033" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_d32a03a6-1d8e-48c9-971a-ae527001dbc4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_6c6715f6-3f96-4442-b25a-e31c37b48033" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_8333174b-cdc6-46a4-998f-2289e18d4d70" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_d32a03a6-1d8e-48c9-971a-ae527001dbc4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_8333174b-cdc6-46a4-998f-2289e18d4d70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_bc83c6df-0156-4489-b82c-f5b43e9e020a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_d32a03a6-1d8e-48c9-971a-ae527001dbc4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_bc83c6df-0156-4489-b82c-f5b43e9e020a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_c5b93999-b93f-4f09-8195-8990b95798de" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_18e41e80-340f-48d8-8032-312876a09d38" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_c5b93999-b93f-4f09-8195-8990b95798de" xlink:to="loc_us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_18e41e80-340f-48d8-8032-312876a09d38" xlink:type="arc" order="2" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_2cd88a1c-0294-46ad-9652-e164ac61ae7d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_18e41e80-340f-48d8-8032-312876a09d38" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_2cd88a1c-0294-46ad-9652-e164ac61ae7d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_2cd88a1c-0294-46ad-9652-e164ac61ae7d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_2cd88a1c-0294-46ad-9652-e164ac61ae7d" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_2cd88a1c-0294-46ad-9652-e164ac61ae7d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_be98d8b7-5ca0-4071-94aa-d1fd214a0a70" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_2cd88a1c-0294-46ad-9652-e164ac61ae7d" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_be98d8b7-5ca0-4071-94aa-d1fd214a0a70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InProcessResearchAndDevelopmentMember_5b65cd95-4487-4d61-a737-48c722958554" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InProcessResearchAndDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_be98d8b7-5ca0-4071-94aa-d1fd214a0a70" xlink:to="loc_us-gaap_InProcessResearchAndDevelopmentMember_5b65cd95-4487-4d61-a737-48c722958554" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_8d5c3a47-26ea-43b6-ab0b-df636d783ae2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_c5b93999-b93f-4f09-8195-8990b95798de" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_8d5c3a47-26ea-43b6-ab0b-df636d783ae2" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/LeasesAdditionalInformationDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#LeasesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/LeasesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionLineItems_c6d00443-d19f-43e3-ac20-598a0d9cc335" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionTable_8bfff9d5-2a5a-40af-8bf5-e0c51c0b8218" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LessorLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_c6d00443-d19f-43e3-ac20-598a0d9cc335" xlink:to="loc_us-gaap_LessorLeaseDescriptionTable_8bfff9d5-2a5a-40af-8bf5-e0c51c0b8218" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e2bf4474-15dd-42cb-96ab-940aa0a47336" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_8bfff9d5-2a5a-40af-8bf5-e0c51c0b8218" xlink:to="loc_srt_RangeAxis_e2bf4474-15dd-42cb-96ab-940aa0a47336" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e2bf4474-15dd-42cb-96ab-940aa0a47336_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e2bf4474-15dd-42cb-96ab-940aa0a47336" xlink:to="loc_srt_RangeMember_e2bf4474-15dd-42cb-96ab-940aa0a47336_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_775e4d13-7483-4c64-9f71-0b696a9aad00" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e2bf4474-15dd-42cb-96ab-940aa0a47336" xlink:to="loc_srt_RangeMember_775e4d13-7483-4c64-9f71-0b696a9aad00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_edd470a2-385f-4be7-aff2-079048c0abd7" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_775e4d13-7483-4c64-9f71-0b696a9aad00" xlink:to="loc_srt_MinimumMember_edd470a2-385f-4be7-aff2-079048c0abd7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_92e5f60b-272a-499c-949f-c61ffb591dfa" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_775e4d13-7483-4c64-9f71-0b696a9aad00" xlink:to="loc_srt_MaximumMember_92e5f60b-272a-499c-949f-c61ffb591dfa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_51e6160f-2109-49b8-9148-d4874a723f02" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_c6d00443-d19f-43e3-ac20-598a0d9cc335" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_51e6160f-2109-49b8-9148-d4874a723f02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_7720a6e5-d90e-4a97-8161-e0510420613a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_c6d00443-d19f-43e3-ac20-598a0d9cc335" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_7720a6e5-d90e-4a97-8161-e0510420613a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments_00170f84-27e2-418b-a0e3-6f4744cb5f85" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeasePayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_c6d00443-d19f-43e3-ac20-598a0d9cc335" xlink:to="loc_us-gaap_OperatingLeasePayments_00170f84-27e2-418b-a0e3-6f4744cb5f85" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/StockholdersEquityDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#StockholdersEquityDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/StockholdersEquityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a78a923d-efd0-40e4-b86a-8bb634035af0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a78a923d-efd0-40e4-b86a-8bb634035af0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_d123f8dd-ac8c-49b5-a659-e513be77415c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a78a923d-efd0-40e4-b86a-8bb634035af0" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_d123f8dd-ac8c-49b5-a659-e513be77415c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_d123f8dd-ac8c-49b5-a659-e513be77415c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_d123f8dd-ac8c-49b5-a659-e513be77415c" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_d123f8dd-ac8c-49b5-a659-e513be77415c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_879e8e62-3778-4039-811b-62b5dc503838" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_d123f8dd-ac8c-49b5-a659-e513be77415c" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_879e8e62-3778-4039-811b-62b5dc503838" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_StifelMember_8709e205-5028-4c05-afdb-20ab1a53f4b6" xlink:href="sitm-20251231.xsd#sitm_StifelMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_879e8e62-3778-4039-811b-62b5dc503838" xlink:to="loc_sitm_StifelMember_8709e205-5028-4c05-afdb-20ab1a53f4b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_aa5456d4-e0e7-4ae9-a277-6cbc085c7145" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a78a923d-efd0-40e4-b86a-8bb634035af0" xlink:to="loc_us-gaap_TypeOfArrangementAxis_aa5456d4-e0e7-4ae9-a277-6cbc085c7145" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_aa5456d4-e0e7-4ae9-a277-6cbc085c7145_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_aa5456d4-e0e7-4ae9-a277-6cbc085c7145" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_aa5456d4-e0e7-4ae9-a277-6cbc085c7145_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_0dd1cfac-9115-49ac-9b51-6d956db0db76" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_aa5456d4-e0e7-4ae9-a277-6cbc085c7145" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_0dd1cfac-9115-49ac-9b51-6d956db0db76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AtTheMarketIssuanceSalesAgreementMember_276104eb-f9e3-4d91-9aa1-89c89da61e57" xlink:href="sitm-20251231.xsd#sitm_AtTheMarketIssuanceSalesAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_0dd1cfac-9115-49ac-9b51-6d956db0db76" xlink:to="loc_sitm_AtTheMarketIssuanceSalesAgreementMember_276104eb-f9e3-4d91-9aa1-89c89da61e57" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_FollowOnPublicOfferingMember_019bda19-6e6d-7778-9a93-aa614e9ae70e" xlink:href="sitm-20251231.xsd#sitm_FollowOnPublicOfferingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_0dd1cfac-9115-49ac-9b51-6d956db0db76" xlink:to="loc_sitm_FollowOnPublicOfferingMember_019bda19-6e6d-7778-9a93-aa614e9ae70e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_0913a9b2-5b86-4ce1-b521-c8833c4f1362" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_0913a9b2-5b86-4ce1-b521-c8833c4f1362" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_bc48e182-f953-43c6-98b1-563ecca9feea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_bc48e182-f953-43c6-98b1-563ecca9feea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_c818c139-1734-4859-83c8-6cf003f1b207" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_c818c139-1734-4859-83c8-6cf003f1b207" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_NumberOfVotesPerShareCommon_5b6a531e-6a22-4058-92f6-9b6e11204353" xlink:href="sitm-20251231.xsd#sitm_NumberOfVotesPerShareCommon"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_sitm_NumberOfVotesPerShareCommon_5b6a531e-6a22-4058-92f6-9b6e11204353" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_7fb4e348-62c4-445c-803b-c500f4317714" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_7fb4e348-62c4-445c-803b-c500f4317714" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PercentageOfSalesCommissionFromCommonStockSold_c89b5e7f-554d-4183-a4bc-c8ea9dc5b4aa" xlink:href="sitm-20251231.xsd#sitm_PercentageOfSalesCommissionFromCommonStockSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_sitm_PercentageOfSalesCommissionFromCommonStockSold_c89b5e7f-554d-4183-a4bc-c8ea9dc5b4aa" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_bd106a64-6d58-40dc-aa13-83271d785fc9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_bd106a64-6d58-40dc-aa13-83271d785fc9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_SaleOfCommonStockPricePerShare_90aa9158-b799-4235-bf6b-47c16612015e" xlink:href="sitm-20251231.xsd#sitm_SaleOfCommonStockPricePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_sitm_SaleOfCommonStockPricePerShare_90aa9158-b799-4235-bf6b-47c16612015e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ProceedsFromIssuanceOfCommonStockNetOfUnderwritingDiscountsAndCommissions_6666b1b0-75cd-433f-8379-a9f4b4f7404d" xlink:href="sitm-20251231.xsd#sitm_ProceedsFromIssuanceOfCommonStockNetOfUnderwritingDiscountsAndCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_sitm_ProceedsFromIssuanceOfCommonStockNetOfUnderwritingDiscountsAndCommissions_6666b1b0-75cd-433f-8379-a9f4b4f7404d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PaymentsForUnderwritingDiscountsAndCommissions_9acc6f40-bd46-4d92-915a-8f327625a1f3" xlink:href="sitm-20251231.xsd#sitm_PaymentsForUnderwritingDiscountsAndCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_sitm_PaymentsForUnderwritingDiscountsAndCommissions_9acc6f40-bd46-4d92-915a-8f327625a1f3" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_59d9d168-1cf2-4e72-96b9-de0d60872505" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfStockIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4740ad1d-f200-484a-8b38-3540183b630f" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_59d9d168-1cf2-4e72-96b9-de0d60872505" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/StockbasedCompensationAdditionalInformationDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#StockbasedCompensationAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/StockbasedCompensationAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5bb1de30-eca5-47cf-9247-c81deddba678" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5bb1de30-eca5-47cf-9247-c81deddba678" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_ebb41fdf-4a96-4527-b13a-8be04e368867" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5bb1de30-eca5-47cf-9247-c81deddba678" xlink:to="loc_us-gaap_PlanNameAxis_ebb41fdf-4a96-4527-b13a-8be04e368867" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_ebb41fdf-4a96-4527-b13a-8be04e368867_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_ebb41fdf-4a96-4527-b13a-8be04e368867" xlink:to="loc_us-gaap_PlanNameDomain_ebb41fdf-4a96-4527-b13a-8be04e368867_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_0f1033c1-70a0-45c8-a3af-b46fb929d4c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_ebb41fdf-4a96-4527-b13a-8be04e368867" xlink:to="loc_us-gaap_PlanNameDomain_0f1033c1-70a0-45c8-a3af-b46fb929d4c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_TwoThousandNineteenStockIncentivePlanMember_da5bbf42-770e-46e2-866a-f499cbec4a20" xlink:href="sitm-20251231.xsd#sitm_TwoThousandNineteenStockIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_0f1033c1-70a0-45c8-a3af-b46fb929d4c3" xlink:to="loc_sitm_TwoThousandNineteenStockIncentivePlanMember_da5bbf42-770e-46e2-866a-f499cbec4a20" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_InducementPlanMember_07f9f844-979c-4fc8-a57e-7e19248df958" xlink:href="sitm-20251231.xsd#sitm_InducementPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_0f1033c1-70a0-45c8-a3af-b46fb929d4c3" xlink:to="loc_sitm_InducementPlanMember_07f9f844-979c-4fc8-a57e-7e19248df958" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_TwentyTwentyFiveGoalsMember_d51ad67e-bb3e-443e-9b94-3640bc3e4d8f" xlink:href="sitm-20251231.xsd#sitm_TwentyTwentyFiveGoalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_0f1033c1-70a0-45c8-a3af-b46fb929d4c3" xlink:to="loc_sitm_TwentyTwentyFiveGoalsMember_d51ad67e-bb3e-443e-9b94-3640bc3e4d8f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_TwentyTwentyTwoGoalsMember_0c0d3183-950a-4564-bcfb-dfe6e6defaa5" xlink:href="sitm-20251231.xsd#sitm_TwentyTwentyTwoGoalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_0f1033c1-70a0-45c8-a3af-b46fb929d4c3" xlink:to="loc_sitm_TwentyTwentyTwoGoalsMember_0c0d3183-950a-4564-bcfb-dfe6e6defaa5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_TwentyTwentyThreeGoalsMember_1a32ba3a-8bd6-471e-b695-6e73859a2c32" xlink:href="sitm-20251231.xsd#sitm_TwentyTwentyThreeGoalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_0f1033c1-70a0-45c8-a3af-b46fb929d4c3" xlink:to="loc_sitm_TwentyTwentyThreeGoalsMember_1a32ba3a-8bd6-471e-b695-6e73859a2c32" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_ab07bfb9-4603-47a9-977e-e223c49dbc39" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5bb1de30-eca5-47cf-9247-c81deddba678" xlink:to="loc_us-gaap_AwardTypeAxis_ab07bfb9-4603-47a9-977e-e223c49dbc39" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ab07bfb9-4603-47a9-977e-e223c49dbc39_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_ab07bfb9-4603-47a9-977e-e223c49dbc39" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ab07bfb9-4603-47a9-977e-e223c49dbc39_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a6c06666-802f-4a49-a9f1-5f8cdb10bc4d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_ab07bfb9-4603-47a9-977e-e223c49dbc39" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a6c06666-802f-4a49-a9f1-5f8cdb10bc4d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_RestrictedStockUnitsLiabilityBasedAwardMember_0b8c9822-591d-4f59-96aa-6432e73e0476" xlink:href="sitm-20251231.xsd#sitm_RestrictedStockUnitsLiabilityBasedAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a6c06666-802f-4a49-a9f1-5f8cdb10bc4d" xlink:to="loc_sitm_RestrictedStockUnitsLiabilityBasedAwardMember_0b8c9822-591d-4f59-96aa-6432e73e0476" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_b438814f-2ec1-444d-96a5-a6327035eb1e" xlink:href="sitm-20251231.xsd#sitm_MultiYearPerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a6c06666-802f-4a49-a9f1-5f8cdb10bc4d" xlink:to="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_b438814f-2ec1-444d-96a5-a6327035eb1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PerformanceRestrictedStockUnitAwardMember_86d88ae2-ef17-44d3-aa14-8844baabd663" xlink:href="sitm-20251231.xsd#sitm_PerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a6c06666-802f-4a49-a9f1-5f8cdb10bc4d" xlink:to="loc_sitm_PerformanceRestrictedStockUnitAwardMember_86d88ae2-ef17-44d3-aa14-8844baabd663" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_TotalStockholderPerformanceRestrictedStockUnitAwardMember_83d5dec1-1aa1-424b-a257-82e6c971c4f4" xlink:href="sitm-20251231.xsd#sitm_TotalStockholderPerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a6c06666-802f-4a49-a9f1-5f8cdb10bc4d" xlink:to="loc_sitm_TotalStockholderPerformanceRestrictedStockUnitAwardMember_83d5dec1-1aa1-424b-a257-82e6c971c4f4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_e5240b1e-f150-40a1-89ab-e3f6a5d14656" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a6c06666-802f-4a49-a9f1-5f8cdb10bc4d" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_e5240b1e-f150-40a1-89ab-e3f6a5d14656" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_35f74525-8ab9-4c94-958d-7b61e544b522" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5bb1de30-eca5-47cf-9247-c81deddba678" xlink:to="loc_srt_RangeAxis_35f74525-8ab9-4c94-958d-7b61e544b522" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_35f74525-8ab9-4c94-958d-7b61e544b522_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_35f74525-8ab9-4c94-958d-7b61e544b522" xlink:to="loc_srt_RangeMember_35f74525-8ab9-4c94-958d-7b61e544b522_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3d8458b5-58cd-4cbe-8694-d76e386fcfb9" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_35f74525-8ab9-4c94-958d-7b61e544b522" xlink:to="loc_srt_RangeMember_3d8458b5-58cd-4cbe-8694-d76e386fcfb9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_02f46c8c-c76b-4395-b8b2-8c967f8d0653" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3d8458b5-58cd-4cbe-8694-d76e386fcfb9" xlink:to="loc_srt_MinimumMember_02f46c8c-c76b-4395-b8b2-8c967f8d0653" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_9251895f-e2c6-41fa-9598-1d09bb1d5a82" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3d8458b5-58cd-4cbe-8694-d76e386fcfb9" xlink:to="loc_srt_MaximumMember_9251895f-e2c6-41fa-9598-1d09bb1d5a82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_af6d6d5b-37f5-48ae-8f0a-6cd586e3f39b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_af6d6d5b-37f5-48ae-8f0a-6cd586e3f39b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_6533bdf5-0328-457b-955b-3d06f1502fcb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_6533bdf5-0328-457b-955b-3d06f1502fcb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_0cd7ac55-b9cb-4404-9265-3d0ad6287669" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_0cd7ac55-b9cb-4404-9265-3d0ad6287669" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AccruedExpensesAndOtherCurrentLiabilities_723e3c0b-7185-490e-967d-78c3e9da1c81" xlink:href="sitm-20251231.xsd#sitm_AccruedExpensesAndOtherCurrentLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_sitm_AccruedExpensesAndOtherCurrentLiabilities_723e3c0b-7185-490e-967d-78c3e9da1c81" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_BonusAndRetentionPlanActualPayoutPercentages_226493af-9d91-4c4c-adef-22fc072db967" xlink:href="sitm-20251231.xsd#sitm_BonusAndRetentionPlanActualPayoutPercentages"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_sitm_BonusAndRetentionPlanActualPayoutPercentages_226493af-9d91-4c4c-adef-22fc072db967" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_cd086292-a27a-4241-bf30-0aac1375e911" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_cd086292-a27a-4241-bf30-0aac1375e911" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PerformancePeriodOfCommonStock_87bf5c61-443c-4351-8e21-070ae14f0aa1" xlink:href="sitm-20251231.xsd#sitm_PerformancePeriodOfCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_sitm_PerformancePeriodOfCommonStock_87bf5c61-443c-4351-8e21-070ae14f0aa1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_cfcc9bff-e907-4015-af5e-026a425fde83" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_cfcc9bff-e907-4015-af5e-026a425fde83" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_18429341-26b1-45f7-9082-8ac3b6946d42" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_18429341-26b1-45f7-9082-8ac3b6946d42" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_fc0568f2-ff9d-462e-846b-b266bbd44b28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_fc0568f2-ff9d-462e-846b-b266bbd44b28" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_f7ed3e7e-a4ff-48f7-a776-1eac7d38cd4d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_f7ed3e7e-a4ff-48f7-a776-1eac7d38cd4d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_58dd6ac0-01b6-489e-a093-1707b7de17bb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_58dd6ac0-01b6-489e-a093-1707b7de17bb" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PerformancePeriod_26dcf19c-6cd1-4a0a-bddd-aa6f5e6f28f1" xlink:href="sitm-20251231.xsd#sitm_PerformancePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_sitm_PerformancePeriod_26dcf19c-6cd1-4a0a-bddd-aa6f5e6f28f1" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod_9e022172-0208-4092-be58-ba366d357230" xlink:href="sitm-20251231.xsd#sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod_9e022172-0208-4092-be58-ba366d357230" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_3c3675ad-041d-40da-9411-515858a17c61" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_3c3675ad-041d-40da-9411-515858a17c61" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_92d9ec87-a8de-4000-ad41-d7f6650ff750" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95a799b4-5df2-4304-9065-feeac9fff880" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1_92d9ec87-a8de-4000-ad41-d7f6650ff750" xlink:type="arc" order="15"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/StockbasedCompensationScheduleofRSUPRSUandMYPSUAwardsActivityDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#StockbasedCompensationScheduleofRSUPRSUandMYPSUAwardsActivityDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/StockbasedCompensationScheduleofRSUPRSUandMYPSUAwardsActivityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fa914c7c-fe44-4aac-b635-2e0a9d23ad99" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2c8e9f53-3904-4121-8cb5-3ee0f42be7ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fa914c7c-fe44-4aac-b635-2e0a9d23ad99" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2c8e9f53-3904-4121-8cb5-3ee0f42be7ba" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_556fa4e1-21c1-4e24-b7e6-aaf11e083a58" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2c8e9f53-3904-4121-8cb5-3ee0f42be7ba" xlink:to="loc_us-gaap_AwardTypeAxis_556fa4e1-21c1-4e24-b7e6-aaf11e083a58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_556fa4e1-21c1-4e24-b7e6-aaf11e083a58_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_556fa4e1-21c1-4e24-b7e6-aaf11e083a58" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_556fa4e1-21c1-4e24-b7e6-aaf11e083a58_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_20b1dd1b-0fd9-4f3c-ad32-b50605c1e4dc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_556fa4e1-21c1-4e24-b7e6-aaf11e083a58" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_20b1dd1b-0fd9-4f3c-ad32-b50605c1e4dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_b5efb365-a62f-425e-aaa0-7c390454ff90" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_20b1dd1b-0fd9-4f3c-ad32-b50605c1e4dc" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_b5efb365-a62f-425e-aaa0-7c390454ff90" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PerformanceRestrictedStockUnitAwardMember_da7a4a76-f762-4a4c-add7-08ade2bb574a" xlink:href="sitm-20251231.xsd#sitm_PerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_20b1dd1b-0fd9-4f3c-ad32-b50605c1e4dc" xlink:to="loc_sitm_PerformanceRestrictedStockUnitAwardMember_da7a4a76-f762-4a4c-add7-08ade2bb574a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_78c71095-e269-4f44-86bd-c5c361cf4173" xlink:href="sitm-20251231.xsd#sitm_MultiYearPerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_20b1dd1b-0fd9-4f3c-ad32-b50605c1e4dc" xlink:to="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_78c71095-e269-4f44-86bd-c5c361cf4173" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c4ae16c5-bd0e-4afe-aebf-f72421048d22" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fa914c7c-fe44-4aac-b635-2e0a9d23ad99" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c4ae16c5-bd0e-4afe-aebf-f72421048d22" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_9830b35a-b7b8-4d0f-b29b-aea675e3db7c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c4ae16c5-bd0e-4afe-aebf-f72421048d22" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_9830b35a-b7b8-4d0f-b29b-aea675e3db7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_69e172b5-0e57-462f-957a-639c96785c16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c4ae16c5-bd0e-4afe-aebf-f72421048d22" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_69e172b5-0e57-462f-957a-639c96785c16" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_13314425-346c-4a6f-af82-fbe1cb2dcd4c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c4ae16c5-bd0e-4afe-aebf-f72421048d22" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_13314425-346c-4a6f-af82-fbe1cb2dcd4c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_cf3a2758-cbb8-4812-bcf8-717720a18b54" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_c4ae16c5-bd0e-4afe-aebf-f72421048d22" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_cf3a2758-cbb8-4812-bcf8-717720a18b54" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_85a3e341-043c-4ccc-b378-9d0519f981ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_23d76211-82a6-4ef8-a845-65bfab1e5bb3" xlink:href="sitm-20251231.xsd#sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fa914c7c-fe44-4aac-b635-2e0a9d23ad99" xlink:to="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_23d76211-82a6-4ef8-a845-65bfab1e5bb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_f8f666da-cdb1-4337-ae65-7f4da4502604" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_23d76211-82a6-4ef8-a845-65bfab1e5bb3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_f8f666da-cdb1-4337-ae65-7f4da4502604" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_6276425a-1c11-4865-86b3-74eac7d69fd8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_23d76211-82a6-4ef8-a845-65bfab1e5bb3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_6276425a-1c11-4865-86b3-74eac7d69fd8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_ad29f59d-5211-4ecc-ab3d-20fa4add78f3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_23d76211-82a6-4ef8-a845-65bfab1e5bb3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_ad29f59d-5211-4ecc-ab3d-20fa4add78f3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_8128d2e2-0a5b-47fc-979f-b71600badfa8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_23d76211-82a6-4ef8-a845-65bfab1e5bb3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_8128d2e2-0a5b-47fc-979f-b71600badfa8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_80523f3f-2783-4549-a2f6-afd3ca590470" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/StockbasedCompensationScheduleofTotalStockBasedCompensationExpenseDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#StockbasedCompensationScheduleofTotalStockBasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/StockbasedCompensationScheduleofTotalStockBasedCompensationExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_87daf96b-e540-4485-8265-7e4279b786e8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_45eb679e-06bb-4816-97fe-a6dd1177a78f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_87daf96b-e540-4485-8265-7e4279b786e8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_45eb679e-06bb-4816-97fe-a6dd1177a78f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_64953ab4-21b7-4559-a40a-2894760c6274" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_45eb679e-06bb-4816-97fe-a6dd1177a78f" xlink:to="loc_us-gaap_AwardTypeAxis_64953ab4-21b7-4559-a40a-2894760c6274" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_64953ab4-21b7-4559-a40a-2894760c6274_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_64953ab4-21b7-4559-a40a-2894760c6274" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_64953ab4-21b7-4559-a40a-2894760c6274_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dcac265d-cad1-4fbf-9c68-9665f7c697e4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_64953ab4-21b7-4559-a40a-2894760c6274" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dcac265d-cad1-4fbf-9c68-9665f7c697e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_EquityAwardMember_fac2d7e1-ae82-4914-8ec3-5db911b17f82" xlink:href="sitm-20251231.xsd#sitm_EquityAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dcac265d-cad1-4fbf-9c68-9665f7c697e4" xlink:to="loc_sitm_EquityAwardMember_fac2d7e1-ae82-4914-8ec3-5db911b17f82" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LiabilityBasedAwardsToBeSettledInEquityMember_aa2f4c13-7600-4ed6-8007-1d8f5992f58f" xlink:href="sitm-20251231.xsd#sitm_LiabilityBasedAwardsToBeSettledInEquityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dcac265d-cad1-4fbf-9c68-9665f7c697e4" xlink:to="loc_sitm_LiabilityBasedAwardsToBeSettledInEquityMember_aa2f4c13-7600-4ed6-8007-1d8f5992f58f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_EquityAndLiabilityBasedAwardsMember_14b82f54-4f91-4cf1-b06a-53cbc3bd810a" xlink:href="sitm-20251231.xsd#sitm_EquityAndLiabilityBasedAwardsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dcac265d-cad1-4fbf-9c68-9665f7c697e4" xlink:to="loc_sitm_EquityAndLiabilityBasedAwardsMember_14b82f54-4f91-4cf1-b06a-53cbc3bd810a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_019c00ab-66b0-78c4-a55a-845863a4c9ae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dcac265d-cad1-4fbf-9c68-9665f7c697e4" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_019c00ab-66b0-78c4-a55a-845863a4c9ae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_RestrictedStockUnitsLiabilityBasedAwardMember_2fb3956c-66d5-4a42-94d9-ffa1eaeef1e5" xlink:href="sitm-20251231.xsd#sitm_RestrictedStockUnitsLiabilityBasedAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dcac265d-cad1-4fbf-9c68-9665f7c697e4" xlink:to="loc_sitm_RestrictedStockUnitsLiabilityBasedAwardMember_2fb3956c-66d5-4a42-94d9-ffa1eaeef1e5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_552728de-9d48-4b45-97fb-39d36256314c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_45eb679e-06bb-4816-97fe-a6dd1177a78f" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_552728de-9d48-4b45-97fb-39d36256314c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_552728de-9d48-4b45-97fb-39d36256314c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_552728de-9d48-4b45-97fb-39d36256314c" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_552728de-9d48-4b45-97fb-39d36256314c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_c292a33a-773e-4772-86a4-b04bab0f5d7f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_552728de-9d48-4b45-97fb-39d36256314c" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_c292a33a-773e-4772-86a4-b04bab0f5d7f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_ba689906-fa4f-4840-bd54-0c99e79c9c28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_c292a33a-773e-4772-86a4-b04bab0f5d7f" xlink:to="loc_us-gaap_CostOfSalesMember_ba689906-fa4f-4840-bd54-0c99e79c9c28" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_bb11da8c-6329-41a1-99cc-46e37345e3f8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_c292a33a-773e-4772-86a4-b04bab0f5d7f" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_bb11da8c-6329-41a1-99cc-46e37345e3f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_c99843f9-ef48-43fa-8223-0325deab193a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_c292a33a-773e-4772-86a4-b04bab0f5d7f" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_c99843f9-ef48-43fa-8223-0325deab193a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_1e734df3-f0e4-449f-b4f1-47609527969c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_87daf96b-e540-4485-8265-7e4279b786e8" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_1e734df3-f0e4-449f-b4f1-47609527969c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount_4c925b78-37c8-4981-b5dd-e37ca8fcb9e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_87daf96b-e540-4485-8265-7e4279b786e8" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount_4c925b78-37c8-4981-b5dd-e37ca8fcb9e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1_6d909a16-9aff-468e-b35b-7b14977a9ddc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_87daf96b-e540-4485-8265-7e4279b786e8" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1_6d909a16-9aff-468e-b35b-7b14977a9ddc" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/StockbasedCompensationScheduleofUnrecognizedCompensationCostsandRelatedWeightedAveragePeriodofRecognitionDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#StockbasedCompensationScheduleofUnrecognizedCompensationCostsandRelatedWeightedAveragePeriodofRecognitionDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/StockbasedCompensationScheduleofUnrecognizedCompensationCostsandRelatedWeightedAveragePeriodofRecognitionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_47b9383f-4947-4db4-b92f-110ebae57e37" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7c7fea43-ab76-4ef7-984f-6185ef716455" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_47b9383f-4947-4db4-b92f-110ebae57e37" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7c7fea43-ab76-4ef7-984f-6185ef716455" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_4d8975e8-c755-4bd1-b46b-195109d08d82" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7c7fea43-ab76-4ef7-984f-6185ef716455" xlink:to="loc_us-gaap_AwardTypeAxis_4d8975e8-c755-4bd1-b46b-195109d08d82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4d8975e8-c755-4bd1-b46b-195109d08d82_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_4d8975e8-c755-4bd1-b46b-195109d08d82" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4d8975e8-c755-4bd1-b46b-195109d08d82_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c0ad983a-472a-47ba-9983-bc2af802b6dd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_4d8975e8-c755-4bd1-b46b-195109d08d82" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c0ad983a-472a-47ba-9983-bc2af802b6dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_9668b999-23fa-4dd2-9e53-9ec191d141ae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c0ad983a-472a-47ba-9983-bc2af802b6dd" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_9668b999-23fa-4dd2-9e53-9ec191d141ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PerformanceRestrictedStockUnitAwardMember_c391af26-e383-47e0-ab5a-b6487756ae80" xlink:href="sitm-20251231.xsd#sitm_PerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c0ad983a-472a-47ba-9983-bc2af802b6dd" xlink:to="loc_sitm_PerformanceRestrictedStockUnitAwardMember_c391af26-e383-47e0-ab5a-b6487756ae80" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_cf455ff1-fef9-4439-9ed7-8796faeb9ec5" xlink:href="sitm-20251231.xsd#sitm_MultiYearPerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c0ad983a-472a-47ba-9983-bc2af802b6dd" xlink:to="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_cf455ff1-fef9-4439-9ed7-8796faeb9ec5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_RestrictedStockUnitsLiabilityBasedAwardMember_63bb1676-d54d-4100-9070-ec824a787f32" xlink:href="sitm-20251231.xsd#sitm_RestrictedStockUnitsLiabilityBasedAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c0ad983a-472a-47ba-9983-bc2af802b6dd" xlink:to="loc_sitm_RestrictedStockUnitsLiabilityBasedAwardMember_63bb1676-d54d-4100-9070-ec824a787f32" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_88fc0bf4-42e9-42e7-b2cc-e746827074e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_47b9383f-4947-4db4-b92f-110ebae57e37" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_88fc0bf4-42e9-42e7-b2cc-e746827074e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_78553cd2-0fe8-4489-b7e6-802653a5dc17" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_47b9383f-4947-4db4-b92f-110ebae57e37" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_78553cd2-0fe8-4489-b7e6-802653a5dc17" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/IncomeTaxesScheduleofCashPaidForIncomeTaxesNetofRefundsReceivedByJurisdictionDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#IncomeTaxesScheduleofCashPaidForIncomeTaxesNetofRefundsReceivedByJurisdictionDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/IncomeTaxesScheduleofCashPaidForIncomeTaxesNetofRefundsReceivedByJurisdictionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxPaidByIndividualJurisdictionLineItems_019c24a7-05ef-75d0-873f-3ec5136ef723" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxPaidByIndividualJurisdictionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxPaidByIndividualJurisdictionTable_019c24a7-05ef-7f55-8d22-8f2f700dfc19" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxPaidByIndividualJurisdictionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxPaidByIndividualJurisdictionLineItems_019c24a7-05ef-75d0-873f-3ec5136ef723" xlink:to="loc_us-gaap_IncomeTaxPaidByIndividualJurisdictionTable_019c24a7-05ef-7f55-8d22-8f2f700dfc19" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_019c24a7-05ef-7d1c-90e5-8b9ea2e81434" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxPaidByIndividualJurisdictionTable_019c24a7-05ef-7f55-8d22-8f2f700dfc19" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_019c24a7-05ef-7d1c-90e5-8b9ea2e81434" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_019c24a7-05ef-7d1c-90e5-8b9ea2e81434_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_019c24a7-05ef-7d1c-90e5-8b9ea2e81434" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_019c24a7-05ef-7d1c-90e5-8b9ea2e81434_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_019c24a7-05ef-7852-b9a5-52716a3d61d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_019c24a7-05ef-7d1c-90e5-8b9ea2e81434" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_019c24a7-05ef-7852-b9a5-52716a3d61d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_IN_019c24a8-0c94-7c1f-bc11-e11418a08bb9" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_IN"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019c24a7-05ef-7852-b9a5-52716a3d61d9" xlink:to="loc_country_IN_019c24a8-0c94-7c1f-bc11-e11418a08bb9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_JP_019c24a8-2a12-754c-b773-36774c6b4655" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_JP"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019c24a7-05ef-7852-b9a5-52716a3d61d9" xlink:to="loc_country_JP_019c24a8-2a12-754c-b773-36774c6b4655" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_UA_019c24a8-52d7-7a1c-8917-7a4727f8d8b5" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_UA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019c24a7-05ef-7852-b9a5-52716a3d61d9" xlink:to="loc_country_UA_019c24a8-52d7-7a1c-8917-7a4727f8d8b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_MY_019c24a8-cb95-71ae-bea6-55d963ddcfee" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_MY"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019c24a7-05ef-7852-b9a5-52716a3d61d9" xlink:to="loc_country_MY_019c24a8-cb95-71ae-bea6-55d963ddcfee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignTaxJurisdictionOtherMember_019c24a9-1e52-7c81-bb4f-53189cf77836" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignTaxJurisdictionOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_019c24a7-05ef-7852-b9a5-52716a3d61d9" xlink:to="loc_us-gaap_ForeignTaxJurisdictionOtherMember_019c24a9-1e52-7c81-bb4f-53189cf77836" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxPaidForeignAfterRefundReceived_019c24a7-05ef-7f5b-87d3-c2a15abeaf6b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxPaidForeignAfterRefundReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxPaidByIndividualJurisdictionLineItems_019c24a7-05ef-75d0-873f-3ec5136ef723" xlink:to="loc_us-gaap_IncomeTaxPaidForeignAfterRefundReceived_019c24a7-05ef-7f5b-87d3-c2a15abeaf6b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaidNet_019c24a7-6dd6-7221-b796-1d0f046dc1b7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxesPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxPaidByIndividualJurisdictionLineItems_019c24a7-05ef-75d0-873f-3ec5136ef723" xlink:to="loc_us-gaap_IncomeTaxesPaidNet_019c24a7-6dd6-7221-b796-1d0f046dc1b7" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/SegmentInformationandOperationsbyGeographicAreaScheduleofSegmentReportingInformationbySegmentDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#SegmentInformationandOperationsbyGeographicAreaScheduleofSegmentReportingInformationbySegmentDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/SegmentInformationandOperationsbyGeographicAreaScheduleofSegmentReportingInformationbySegmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_a7e64d48-cafc-44a6-a9b2-ab34f5bc0367" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b72f9b26-395b-4d23-945f-89cac32e8084" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_a7e64d48-cafc-44a6-a9b2-ab34f5bc0367" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b72f9b26-395b-4d23-945f-89cac32e8084" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_f46b57c3-86c7-4f99-9360-288637ca19f9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b72f9b26-395b-4d23-945f-89cac32e8084" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_f46b57c3-86c7-4f99-9360-288637ca19f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_f46b57c3-86c7-4f99-9360-288637ca19f9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_f46b57c3-86c7-4f99-9360-288637ca19f9" xlink:to="loc_us-gaap_SegmentDomain_f46b57c3-86c7-4f99-9360-288637ca19f9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_3eeb4249-f396-4102-b782-3667fdca4908" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_f46b57c3-86c7-4f99-9360-288637ca19f9" xlink:to="loc_us-gaap_SegmentDomain_3eeb4249-f396-4102-b782-3667fdca4908" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ReportableSegmentMember_bc76ad24-7d4a-4538-8088-052abfd7bc95" xlink:href="sitm-20251231.xsd#sitm_ReportableSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_3eeb4249-f396-4102-b782-3667fdca4908" xlink:to="loc_sitm_ReportableSegmentMember_bc76ad24-7d4a-4538-8088-052abfd7bc95" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_4d0d3385-cba0-4658-8d50-444ed1469c77" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_a7e64d48-cafc-44a6-a9b2-ab34f5bc0367" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_4d0d3385-cba0-4658-8d50-444ed1469c77" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_f673033a-638f-43de-81b0-dd5839913e66" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_a7e64d48-cafc-44a6-a9b2-ab34f5bc0367" xlink:to="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_f673033a-638f-43de-81b0-dd5839913e66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductionAndDistributionCosts_381de715-b54b-4c14-8c4b-8213eb21283a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProductionAndDistributionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_f673033a-638f-43de-81b0-dd5839913e66" xlink:to="loc_us-gaap_ProductionAndDistributionCosts_381de715-b54b-4c14-8c4b-8213eb21283a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_0bd9dc23-f222-472f-91f4-b57beb1ed9e0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_f673033a-638f-43de-81b0-dd5839913e66" xlink:to="loc_us-gaap_Depreciation_0bd9dc23-f222-472f-91f4-b57beb1ed9e0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentForAmortization_904444a3-10e5-4b8d-bf5d-1cb5b04a6cd8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentForAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_f673033a-638f-43de-81b0-dd5839913e66" xlink:to="loc_us-gaap_AdjustmentForAmortization_904444a3-10e5-4b8d-bf5d-1cb5b04a6cd8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_OtherManufacturingOverheads_4ccfa4e6-a3c4-4011-8f3a-2e20a1116e0d" xlink:href="sitm-20251231.xsd#sitm_OtherManufacturingOverheads"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_f673033a-638f-43de-81b0-dd5839913e66" xlink:to="loc_sitm_OtherManufacturingOverheads_4ccfa4e6-a3c4-4011-8f3a-2e20a1116e0d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_fc54e528-8f43-41d4-8ecd-466b29781d28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_f673033a-638f-43de-81b0-dd5839913e66" xlink:to="loc_us-gaap_GrossProfit_fc54e528-8f43-41d4-8ecd-466b29781d28" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationOperatingIncomeLossAbstract_e7d1bb51-0d42-40da-a35a-072225af761f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationOperatingIncomeLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_a7e64d48-cafc-44a6-a9b2-ab34f5bc0367" xlink:to="loc_us-gaap_SegmentReportingInformationOperatingIncomeLossAbstract_e7d1bb51-0d42-40da-a35a-072225af761f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_50057e36-9658-46bf-ae5a-5669e1dae13b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationOperatingIncomeLossAbstract_e7d1bb51-0d42-40da-a35a-072225af761f" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_50057e36-9658-46bf-ae5a-5669e1dae13b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_a6e18995-06fa-4dfc-addc-5017a6afc073" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationOperatingIncomeLossAbstract_e7d1bb51-0d42-40da-a35a-072225af761f" xlink:to="loc_us-gaap_InvestmentIncomeInterest_a6e18995-06fa-4dfc-addc-5017a6afc073" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingOtherItemAmount_f9bcfe03-fe2a-4fd2-a939-02a26cd36a20" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingOtherItemAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationOperatingIncomeLossAbstract_e7d1bb51-0d42-40da-a35a-072225af761f" xlink:to="loc_us-gaap_SegmentReportingOtherItemAmount_f9bcfe03-fe2a-4fd2-a939-02a26cd36a20" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_a20716ee-405d-443d-964d-694e7662889e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_a7e64d48-cafc-44a6-a9b2-ab34f5bc0367" xlink:to="loc_us-gaap_NetIncomeLoss_a20716ee-405d-443d-964d-694e7662889e" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/SegmentInformationandOperationsbyGeographicAreaScheduleofRevenuebyCountryDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#SegmentInformationandOperationsbyGeographicAreaScheduleofRevenuebyCountryDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/SegmentInformationandOperationsbyGeographicAreaScheduleofRevenuebyCountryDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_3bcac9bd-ba52-4e83-9435-f8162d01a846" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9918519b-4db8-40f3-b3b3-36aa13436952" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_3bcac9bd-ba52-4e83-9435-f8162d01a846" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9918519b-4db8-40f3-b3b3-36aa13436952" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_739a08a0-9bfb-40f1-98b1-b840e2a85118" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9918519b-4db8-40f3-b3b3-36aa13436952" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_739a08a0-9bfb-40f1-98b1-b840e2a85118" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_739a08a0-9bfb-40f1-98b1-b840e2a85118_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_739a08a0-9bfb-40f1-98b1-b840e2a85118" xlink:to="loc_us-gaap_SegmentDomain_739a08a0-9bfb-40f1-98b1-b840e2a85118_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a8153fec-3bd3-444d-b89c-b4dfd70d591e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_739a08a0-9bfb-40f1-98b1-b840e2a85118" xlink:to="loc_us-gaap_SegmentDomain_a8153fec-3bd3-444d-b89c-b4dfd70d591e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ReportableSegmentMember_3d5d736f-5bd0-495c-b130-5ac9ea98a7be" xlink:href="sitm-20251231.xsd#sitm_ReportableSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a8153fec-3bd3-444d-b89c-b4dfd70d591e" xlink:to="loc_sitm_ReportableSegmentMember_3d5d736f-5bd0-495c-b130-5ac9ea98a7be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_4d415ac6-1fa9-4f45-a169-7e71b696b15b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9918519b-4db8-40f3-b3b3-36aa13436952" xlink:to="loc_srt_StatementGeographicalAxis_4d415ac6-1fa9-4f45-a169-7e71b696b15b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_4d415ac6-1fa9-4f45-a169-7e71b696b15b_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_4d415ac6-1fa9-4f45-a169-7e71b696b15b" xlink:to="loc_srt_SegmentGeographicalDomain_4d415ac6-1fa9-4f45-a169-7e71b696b15b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_3896805e-57cf-45c6-8383-82cb20c05949" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_4d415ac6-1fa9-4f45-a169-7e71b696b15b" xlink:to="loc_srt_SegmentGeographicalDomain_3896805e-57cf-45c6-8383-82cb20c05949" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_HK_07bcf449-1e2e-40b2-934e-0c4c2cf650c8" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_HK"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_3896805e-57cf-45c6-8383-82cb20c05949" xlink:to="loc_country_HK_07bcf449-1e2e-40b2-934e-0c4c2cf650c8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_TW_39b74988-b486-4c90-9d1e-584ba8f8d4e6" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_TW"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_3896805e-57cf-45c6-8383-82cb20c05949" xlink:to="loc_country_TW_39b74988-b486-4c90-9d1e-584ba8f8d4e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_27f67014-6c4d-4084-9b23-ab85ced55697" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_3896805e-57cf-45c6-8383-82cb20c05949" xlink:to="loc_country_US_27f67014-6c4d-4084-9b23-ab85ced55697" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_SG_95463d80-d86e-4911-b38e-38eea85ee111" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_SG"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_3896805e-57cf-45c6-8383-82cb20c05949" xlink:to="loc_country_SG_95463d80-d86e-4911-b38e-38eea85ee111" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_OtherCountriesMember_cff124cc-bbb8-4902-84d5-d63f20f8ab86" xlink:href="sitm-20251231.xsd#sitm_OtherCountriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_3896805e-57cf-45c6-8383-82cb20c05949" xlink:to="loc_sitm_OtherCountriesMember_cff124cc-bbb8-4902-84d5-d63f20f8ab86" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_05c7f4f3-7bfe-4151-a711-17ad74613b3d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9918519b-4db8-40f3-b3b3-36aa13436952" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_05c7f4f3-7bfe-4151-a711-17ad74613b3d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_05c7f4f3-7bfe-4151-a711-17ad74613b3d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_05c7f4f3-7bfe-4151-a711-17ad74613b3d" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_05c7f4f3-7bfe-4151-a711-17ad74613b3d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_03a1654e-0447-43b9-8cda-e8ad2ce78908" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_05c7f4f3-7bfe-4151-a711-17ad74613b3d" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_03a1654e-0447-43b9-8cda-e8ad2ce78908" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_518b3b1b-644e-42ff-9573-d8b86dee12bb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_03a1654e-0447-43b9-8cda-e8ad2ce78908" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_518b3b1b-644e-42ff-9573-d8b86dee12bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_f340702b-3f69-4511-aec3-8d5121b36aa5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_9918519b-4db8-40f3-b3b3-36aa13436952" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_f340702b-3f69-4511-aec3-8d5121b36aa5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_f340702b-3f69-4511-aec3-8d5121b36aa5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_f340702b-3f69-4511-aec3-8d5121b36aa5" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_f340702b-3f69-4511-aec3-8d5121b36aa5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_6f9ad3f8-17d3-4adb-84f3-3984946a2587" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_f340702b-3f69-4511-aec3-8d5121b36aa5" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_6f9ad3f8-17d3-4adb-84f3-3984946a2587" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicConcentrationRiskMember_d97f8e54-bca6-4ffd-9c7d-534133154872" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeographicConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_6f9ad3f8-17d3-4adb-84f3-3984946a2587" xlink:to="loc_us-gaap_GeographicConcentrationRiskMember_d97f8e54-bca6-4ffd-9c7d-534133154872" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_807760eb-b30a-476f-bab2-92ef67a2dd16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_3bcac9bd-ba52-4e83-9435-f8162d01a846" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_807760eb-b30a-476f-bab2-92ef67a2dd16" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/SegmentInformationandOperationsbyGeographicAreaScheduleofPropertyandEquipmentAttributabletoOperationsDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#SegmentInformationandOperationsbyGeographicAreaScheduleofPropertyandEquipmentAttributabletoOperationsDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/SegmentInformationandOperationsbyGeographicAreaScheduleofPropertyandEquipmentAttributabletoOperationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_7b674d07-d570-45e0-847f-789386a2661b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b10666a5-c6ab-452a-81c1-aed7a7db787b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_7b674d07-d570-45e0-847f-789386a2661b" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b10666a5-c6ab-452a-81c1-aed7a7db787b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_75d47e2a-53e1-47bb-a9ae-4d6e1a27975c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b10666a5-c6ab-452a-81c1-aed7a7db787b" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_75d47e2a-53e1-47bb-a9ae-4d6e1a27975c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_75d47e2a-53e1-47bb-a9ae-4d6e1a27975c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_75d47e2a-53e1-47bb-a9ae-4d6e1a27975c" xlink:to="loc_us-gaap_SegmentDomain_75d47e2a-53e1-47bb-a9ae-4d6e1a27975c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_bc602d87-b3a7-4567-9cdf-127f53fb6238" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_75d47e2a-53e1-47bb-a9ae-4d6e1a27975c" xlink:to="loc_us-gaap_SegmentDomain_bc602d87-b3a7-4567-9cdf-127f53fb6238" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ReportableSegmentMember_b7e94a2d-f1b0-4029-8ff2-3359b2118071" xlink:href="sitm-20251231.xsd#sitm_ReportableSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_bc602d87-b3a7-4567-9cdf-127f53fb6238" xlink:to="loc_sitm_ReportableSegmentMember_b7e94a2d-f1b0-4029-8ff2-3359b2118071" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_2cd59fc8-2134-4364-a7e5-26e4136cf3ad" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b10666a5-c6ab-452a-81c1-aed7a7db787b" xlink:to="loc_srt_StatementGeographicalAxis_2cd59fc8-2134-4364-a7e5-26e4136cf3ad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_2cd59fc8-2134-4364-a7e5-26e4136cf3ad_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_2cd59fc8-2134-4364-a7e5-26e4136cf3ad" xlink:to="loc_srt_SegmentGeographicalDomain_2cd59fc8-2134-4364-a7e5-26e4136cf3ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_98f9eea0-58d6-4615-a058-54448d929214" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_2cd59fc8-2134-4364-a7e5-26e4136cf3ad" xlink:to="loc_srt_SegmentGeographicalDomain_98f9eea0-58d6-4615-a058-54448d929214" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_c3769c01-a6a5-4e78-89a6-fb9ee2703c42" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_98f9eea0-58d6-4615-a058-54448d929214" xlink:to="loc_country_US_c3769c01-a6a5-4e78-89a6-fb9ee2703c42" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_TW_3471436e-c6e2-4b51-ba40-e703fdfdcced" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_TW"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_98f9eea0-58d6-4615-a058-54448d929214" xlink:to="loc_country_TW_3471436e-c6e2-4b51-ba40-e703fdfdcced" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_MY_6f328834-6942-4c00-b914-a30a48506d48" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_MY"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_98f9eea0-58d6-4615-a058-54448d929214" xlink:to="loc_country_MY_6f328834-6942-4c00-b914-a30a48506d48" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_SG_019bda28-51a3-722b-90c6-8d2ea28df50b" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_SG"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_98f9eea0-58d6-4615-a058-54448d929214" xlink:to="loc_country_SG_019bda28-51a3-722b-90c6-8d2ea28df50b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_OtherCountriesMember_3187c947-89a9-48c9-aee4-cfa939aea953" xlink:href="sitm-20251231.xsd#sitm_OtherCountriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_98f9eea0-58d6-4615-a058-54448d929214" xlink:to="loc_sitm_OtherCountriesMember_3187c947-89a9-48c9-aee4-cfa939aea953" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_198eb01e-6e5f-4c42-9f08-834a2446d167" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_7b674d07-d570-45e0-847f-789386a2661b" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_198eb01e-6e5f-4c42-9f08-834a2446d167" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/SubsequentEventsDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#SubsequentEventsDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_0335379a-b11c-4a6f-9dbf-e870187ec146" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_b6dee7f7-17d0-42fe-91f0-406064b73fc3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_0335379a-b11c-4a6f-9dbf-e870187ec146" xlink:to="loc_us-gaap_SubsequentEventTable_b6dee7f7-17d0-42fe-91f0-406064b73fc3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_58ea1361-a7d4-4c20-af99-e4cb0fce9a84" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_b6dee7f7-17d0-42fe-91f0-406064b73fc3" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_58ea1361-a7d4-4c20-af99-e4cb0fce9a84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_58ea1361-a7d4-4c20-af99-e4cb0fce9a84_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_58ea1361-a7d4-4c20-af99-e4cb0fce9a84" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_58ea1361-a7d4-4c20-af99-e4cb0fce9a84_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_19ef99ce-d8ab-4374-b55a-42630bdd125b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_58ea1361-a7d4-4c20-af99-e4cb0fce9a84" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_19ef99ce-d8ab-4374-b55a-42630bdd125b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_e5f59fd6-2923-41a5-a2fc-430029ad5e84" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_19ef99ce-d8ab-4374-b55a-42630bdd125b" xlink:to="loc_us-gaap_SubsequentEventMember_e5f59fd6-2923-41a5-a2fc-430029ad5e84" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionAxis_019c364b-a51b-7ed5-8ad3-1c625aaafc6b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_b6dee7f7-17d0-42fe-91f0-406064b73fc3" xlink:to="loc_us-gaap_AssetAcquisitionAxis_019c364b-a51b-7ed5-8ad3-1c625aaafc6b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain_019c364b-a51b-7ed5-8ad3-1c625aaafc6b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetAcquisitionAxis_019c364b-a51b-7ed5-8ad3-1c625aaafc6b" xlink:to="loc_us-gaap_AssetAcquisitionDomain_019c364b-a51b-7ed5-8ad3-1c625aaafc6b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain_019c364b-a51b-7f18-9dda-3029198f5d67" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetAcquisitionAxis_019c364b-a51b-7ed5-8ad3-1c625aaafc6b" xlink:to="loc_us-gaap_AssetAcquisitionDomain_019c364b-a51b-7f18-9dda-3029198f5d67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_RenesasAssetPurchaseAgreementMember_019c364c-30fd-76cc-9cfd-16b61eb3f6e3" xlink:href="sitm-20251231.xsd#sitm_RenesasAssetPurchaseAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetAcquisitionDomain_019c364b-a51b-7f18-9dda-3029198f5d67" xlink:to="loc_sitm_RenesasAssetPurchaseAgreementMember_019c364c-30fd-76cc-9cfd-16b61eb3f6e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_019c3650-5e49-7255-bd71-a0fcd9fc2536" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_b6dee7f7-17d0-42fe-91f0-406064b73fc3" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_019c3650-5e49-7255-bd71-a0fcd9fc2536" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_019c3650-5e49-7255-bd71-a0fcd9fc2536_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_019c3650-5e49-7255-bd71-a0fcd9fc2536" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_019c3650-5e49-7255-bd71-a0fcd9fc2536_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_019c3650-5e49-7546-9046-aa049f485f7b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_019c3650-5e49-7255-bd71-a0fcd9fc2536" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_019c3650-5e49-7546-9046-aa049f485f7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_WellsFargoMember_019c3651-0bc3-747a-bd8c-7bdf66b6af30" xlink:href="sitm-20251231.xsd#sitm_WellsFargoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_019c3650-5e49-7546-9046-aa049f485f7b" xlink:to="loc_sitm_WellsFargoMember_019c3651-0bc3-747a-bd8c-7bdf66b6af30" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019c4478-f91e-7101-8856-c60912c01dce" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_b6dee7f7-17d0-42fe-91f0-406064b73fc3" xlink:to="loc_srt_RangeAxis_019c4478-f91e-7101-8856-c60912c01dce" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019c4478-f91e-7101-8856-c60912c01dce_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019c4478-f91e-7101-8856-c60912c01dce" xlink:to="loc_srt_RangeMember_019c4478-f91e-7101-8856-c60912c01dce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019c4478-f91e-7562-8ff8-abb2a4243d64" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019c4478-f91e-7101-8856-c60912c01dce" xlink:to="loc_srt_RangeMember_019c4478-f91e-7562-8ff8-abb2a4243d64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019c4479-1bc4-7cf6-9cdc-2050c2c8c6cf" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019c4478-f91e-7562-8ff8-abb2a4243d64" xlink:to="loc_srt_MinimumMember_019c4479-1bc4-7cf6-9cdc-2050c2c8c6cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019c4479-378b-754d-ac70-691e71362ec8" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019c4478-f91e-7562-8ff8-abb2a4243d64" xlink:to="loc_srt_MaximumMember_019c4479-378b-754d-ac70-691e71362ec8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_019c447c-6ce8-7202-b55e-10033a104973" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_b6dee7f7-17d0-42fe-91f0-406064b73fc3" xlink:to="loc_us-gaap_CreditFacilityAxis_019c447c-6ce8-7202-b55e-10033a104973" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019c447c-6ce8-7202-b55e-10033a104973_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_019c447c-6ce8-7202-b55e-10033a104973" xlink:to="loc_us-gaap_CreditFacilityDomain_019c447c-6ce8-7202-b55e-10033a104973_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_019c447c-6ce8-7204-9384-6a82cdb7e57b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_019c447c-6ce8-7202-b55e-10033a104973" xlink:to="loc_us-gaap_CreditFacilityDomain_019c447c-6ce8-7204-9384-6a82cdb7e57b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_019c447c-80c0-7005-875d-887c546d15ec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_019c447c-6ce8-7204-9384-6a82cdb7e57b" xlink:to="loc_us-gaap_LetterOfCreditMember_019c447c-80c0-7005-875d-887c546d15ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_019c447c-f3e6-7532-a437-af087f2a4152" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_b6dee7f7-17d0-42fe-91f0-406064b73fc3" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_019c447c-f3e6-7532-a437-af087f2a4152" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019c447c-f3e6-7532-a437-af087f2a4152_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019c447c-f3e6-7532-a437-af087f2a4152" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019c447c-f3e6-7532-a437-af087f2a4152_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019c447c-f3e6-75b9-9ae0-5020a4decd0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019c447c-f3e6-7532-a437-af087f2a4152" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019c447c-f3e6-75b9-9ae0-5020a4decd0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BridgeLoanMember_019c447d-0f60-764d-9d18-0d1c5e9dd4da" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BridgeLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_019c447c-f3e6-75b9-9ae0-5020a4decd0a" xlink:to="loc_us-gaap_BridgeLoanMember_019c447d-0f60-764d-9d18-0d1c5e9dd4da" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PaymentsforAssetAcquisitions_019c364b-a51b-7d85-95a2-79625e3e934a" xlink:href="sitm-20251231.xsd#sitm_PaymentsforAssetAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_0335379a-b11c-4a6f-9dbf-e870187ec146" xlink:to="loc_sitm_PaymentsforAssetAcquisitions_019c364b-a51b-7d85-95a2-79625e3e934a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AssetAcquisitionConsiderationTransferredEquityInterestSharesIssuedAndIssuableNumberOfShares_019c3648-bb04-770e-997d-db70b656f8ba" xlink:href="sitm-20251231.xsd#sitm_AssetAcquisitionConsiderationTransferredEquityInterestSharesIssuedAndIssuableNumberOfShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_0335379a-b11c-4a6f-9dbf-e870187ec146" xlink:to="loc_sitm_AssetAcquisitionConsiderationTransferredEquityInterestSharesIssuedAndIssuableNumberOfShares_019c3648-bb04-770e-997d-db70b656f8ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AssetAcquisitionConsecutiveTradingDays_019c3649-c79e-7efc-9591-aadbf6baa0c0" xlink:href="sitm-20251231.xsd#sitm_AssetAcquisitionConsecutiveTradingDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_0335379a-b11c-4a6f-9dbf-e870187ec146" xlink:to="loc_sitm_AssetAcquisitionConsecutiveTradingDays_019c3649-c79e-7efc-9591-aadbf6baa0c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AssetAcquisitionConsiderationTransferredEquityInterestsIssuedAndIssuableSharePriceFloorPrice_019c3623-1a14-75b9-9fc3-aa77bcdd0848" xlink:href="sitm-20251231.xsd#sitm_AssetAcquisitionConsiderationTransferredEquityInterestsIssuedAndIssuableSharePriceFloorPrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_0335379a-b11c-4a6f-9dbf-e870187ec146" xlink:to="loc_sitm_AssetAcquisitionConsiderationTransferredEquityInterestsIssuedAndIssuableSharePriceFloorPrice_019c3623-1a14-75b9-9fc3-aa77bcdd0848" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019c364f-a7ac-7391-ae8b-3ca1823154a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_0335379a-b11c-4a6f-9dbf-e870187ec146" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019c364f-a7ac-7391-ae8b-3ca1823154a0" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/ScheduleIIValuationandQualifyingAccountsDetails" xlink:type="simple" xlink:href="sitm-20251231.xsd#ScheduleIIValuationandQualifyingAccountsDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/ScheduleIIValuationandQualifyingAccountsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_6c4ea37b-a98a-4c7b-8626-ed389be25307" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ValuationAndQualifyingAccountsDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_9246d088-feb6-49af-a66c-075d72e7e75d" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ValuationAndQualifyingAccountsDisclosureTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_6c4ea37b-a98a-4c7b-8626-ed389be25307" xlink:to="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_9246d088-feb6-49af-a66c-075d72e7e75d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_8b3c359d-6a40-4564-9f25-381531f9fb9f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_9246d088-feb6-49af-a66c-075d72e7e75d" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_8b3c359d-6a40-4564-9f25-381531f9fb9f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_8b3c359d-6a40-4564-9f25-381531f9fb9f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_8b3c359d-6a40-4564-9f25-381531f9fb9f" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_8b3c359d-6a40-4564-9f25-381531f9fb9f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_2d3e1771-2572-45f7-be8e-38f05ff59815" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_8b3c359d-6a40-4564-9f25-381531f9fb9f" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_2d3e1771-2572-45f7-be8e-38f05ff59815" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForCreditLossMember_1d26193f-9b57-465c-9fae-5981ef51884d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForCreditLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_2d3e1771-2572-45f7-be8e-38f05ff59815" xlink:to="loc_us-gaap_AllowanceForCreditLossMember_1d26193f-9b57-465c-9fae-5981ef51884d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_27b2a610-f160-440b-be5d-08282ecda327" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_2d3e1771-2572-45f7-be8e-38f05ff59815" xlink:to="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_27b2a610-f160-440b-be5d-08282ecda327" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6d05b017-6a7a-4a08-97ae-ccf676ec5495" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_6c4ea37b-a98a-4c7b-8626-ed389be25307" xlink:to="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6d05b017-6a7a-4a08-97ae-ccf676ec5495" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_d240c8d5-23a1-4428-b56c-7cd3fafeedfa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6d05b017-6a7a-4a08-97ae-ccf676ec5495" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesBalance_d240c8d5-23a1-4428-b56c-7cd3fafeedfa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ValuationAllowancesAndReservesAdditionsChargedToExpensesOrOtherAccounts_56336cc6-dcbc-4663-94d0-7f7c428b15da" xlink:href="sitm-20251231.xsd#sitm_ValuationAllowancesAndReservesAdditionsChargedToExpensesOrOtherAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6d05b017-6a7a-4a08-97ae-ccf676ec5495" xlink:to="loc_sitm_ValuationAllowancesAndReservesAdditionsChargedToExpensesOrOtherAccounts_56336cc6-dcbc-4663-94d0-7f7c428b15da" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ValuationAllowancesAndReservesDeductionsCreditedToExpensesOrOtherAccounts_8e0af842-75cb-4f88-87e1-ed680ef0b142" xlink:href="sitm-20251231.xsd#sitm_ValuationAllowancesAndReservesDeductionsCreditedToExpensesOrOtherAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6d05b017-6a7a-4a08-97ae-ccf676ec5495" xlink:to="loc_sitm_ValuationAllowancesAndReservesDeductionsCreditedToExpensesOrOtherAccounts_8e0af842-75cb-4f88-87e1-ed680ef0b142" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_b546d064-1322-48d1-8a24-2e6d42432662" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-roles-2025.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:type="arc" order="691"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AccruedExpensesAndOtherCurrentLiabilities_da7fd8ce-3be6-4009-987a-d8dd832431b3" xlink:href="sitm-20251231.xsd#sitm_AccruedExpensesAndOtherCurrentLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="loc_sitm_AccruedExpensesAndOtherCurrentLiabilities_da7fd8ce-3be6-4009-987a-d8dd832431b3" xlink:type="arc" order="41"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#IndividualsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd#ecd_AllIndividualsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LionelBonnotMember_357b6192-0827-45b8-bc9b-235dabfc8e63" xlink:href="sitm-20251231.xsd#sitm_LionelBonnotMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_sitm_LionelBonnotMember_357b6192-0827-45b8-bc9b-235dabfc8e63" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_FariborzAssaderaghiMember_019bda2b-236c-73b4-9a1d-e6d4ea33e302" xlink:href="sitm-20251231.xsd#sitm_FariborzAssaderaghiMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_sitm_FariborzAssaderaghiMember_019bda2b-236c-73b4-9a1d-e6d4ea33e302" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PiyushSevaliaMember_b55ad776-6ca5-4197-b346-276d13e18da8" xlink:href="sitm-20251231.xsd#sitm_PiyushSevaliaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_sitm_PiyushSevaliaMember_b55ad776-6ca5-4197-b346-276d13e18da8" xlink:type="arc" order="4"/>
  </link:definitionLink>
</link:linkbase>
