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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2024 Workiva-->
<!--r:32a528f2-73e2-4e51-a5af-74e5b68cd7ac,g:10003bf7-9b81-4d82-9b21-77d3ed51354a-->
<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/CondensedConsolidatedStatementsOfStockholdersEquity" xlink:type="simple" xlink:href="sitm-20240930.xsd#CondensedConsolidatedStatementsOfStockholdersEquity"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/CondensedConsolidatedStatementsOfStockholdersEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_6dd04399-4700-49fd-a3c0-4ec13319495e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_dbae329a-0fd6-452a-b519-d22fa9beb614" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_6dd04399-4700-49fd-a3c0-4ec13319495e" xlink:to="loc_us-gaap_StatementTable_dbae329a-0fd6-452a-b519-d22fa9beb614" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_ac68fae3-b2bc-4f4d-a952-84c73cf2b959" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_dbae329a-0fd6-452a-b519-d22fa9beb614" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_ac68fae3-b2bc-4f4d-a952-84c73cf2b959" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_ac68fae3-b2bc-4f4d-a952-84c73cf2b959_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_ac68fae3-b2bc-4f4d-a952-84c73cf2b959" xlink:to="loc_us-gaap_EquityComponentDomain_ac68fae3-b2bc-4f4d-a952-84c73cf2b959_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_2fb91aea-15e0-4de2-925d-dda97d667ad1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_ac68fae3-b2bc-4f4d-a952-84c73cf2b959" xlink:to="loc_us-gaap_EquityComponentDomain_2fb91aea-15e0-4de2-925d-dda97d667ad1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_9f230137-e7d6-403e-9740-602c2f2ae5fa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_2fb91aea-15e0-4de2-925d-dda97d667ad1" xlink:to="loc_us-gaap_CommonStockMember_9f230137-e7d6-403e-9740-602c2f2ae5fa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_fcfbfd8d-32d7-4884-9761-efb4178266fa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_2fb91aea-15e0-4de2-925d-dda97d667ad1" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_fcfbfd8d-32d7-4884-9761-efb4178266fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_eaa14544-3bd4-4c33-b5ca-16ab36098d9e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_2fb91aea-15e0-4de2-925d-dda97d667ad1" xlink:to="loc_us-gaap_RetainedEarningsMember_eaa14544-3bd4-4c33-b5ca-16ab36098d9e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3794b6b7-845b-4e8d-adc0-40039286366c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6dd04399-4700-49fd-a3c0-4ec13319495e" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3794b6b7-845b-4e8d-adc0-40039286366c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_d75e8528-e2ba-4554-bf70-25e6c836d2f3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3794b6b7-845b-4e8d-adc0-40039286366c" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_d75e8528-e2ba-4554-bf70-25e6c836d2f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_f348acdb-0f37-49b1-993b-42ddf8898895" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3794b6b7-845b-4e8d-adc0-40039286366c" xlink:to="loc_us-gaap_StockholdersEquity_f348acdb-0f37-49b1-993b-42ddf8898895" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_d79d759f-cb65-4f73-b590-4261d6a76252" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3794b6b7-845b-4e8d-adc0-40039286366c" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_d79d759f-cb65-4f73-b590-4261d6a76252" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_65739208-0a6e-459e-8cb4-59d446d118f1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3794b6b7-845b-4e8d-adc0-40039286366c" xlink:to="loc_us-gaap_NetIncomeLoss_65739208-0a6e-459e-8cb4-59d446d118f1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_67b9b829-ed6c-495e-95bb-4b41a0a7c158" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3794b6b7-845b-4e8d-adc0-40039286366c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_67b9b829-ed6c-495e-95bb-4b41a0a7c158" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_e574994e-a290-40c6-8e72-324833b8ca8d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3794b6b7-845b-4e8d-adc0-40039286366c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_e574994e-a290-40c6-8e72-324833b8ca8d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings_660526ef-80bf-44af-9043-ffaa5eefa544" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3794b6b7-845b-4e8d-adc0-40039286366c" xlink:to="loc_us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings_660526ef-80bf-44af-9043-ffaa5eefa544" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockValueSharesIssuedNetOfTaxWithholdings_0fe5b485-d137-4dc3-9d05-26bd617c45c2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockValueSharesIssuedNetOfTaxWithholdings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_3794b6b7-845b-4e8d-adc0-40039286366c" xlink:to="loc_us-gaap_RestrictedStockValueSharesIssuedNetOfTaxWithholdings_0fe5b485-d137-4dc3-9d05-26bd617c45c2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_a5c5b270-9846-44e4-a2e7-27449be75616" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_6ea04613-7b6f-4e89-9f61-4c5dc599b4e8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/AcquisitionsAdditionalInformationDetails" xlink:type="simple" xlink:href="sitm-20240930.xsd#AcquisitionsAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/AcquisitionsAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_2cb07590-2ec5-441b-ac5c-ece14af734cf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_4bf54ea1-9d35-44c0-9b3f-31506215690a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2cb07590-2ec5-441b-ac5c-ece14af734cf" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_4bf54ea1-9d35-44c0-9b3f-31506215690a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_0c99c798-f0af-467c-b27c-12543c427375" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_4bf54ea1-9d35-44c0-9b3f-31506215690a" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_0c99c798-f0af-467c-b27c-12543c427375" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0c99c798-f0af-467c-b27c-12543c427375_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0c99c798-f0af-467c-b27c-12543c427375" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0c99c798-f0af-467c-b27c-12543c427375_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fdb9f2ff-95d4-4278-9d04-330f77625e13" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_0c99c798-f0af-467c-b27c-12543c427375" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fdb9f2ff-95d4-4278-9d04-330f77625e13" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AuraMember_63357aaa-0897-45de-af65-b83c10873e02" xlink:href="sitm-20240930.xsd#sitm_AuraMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fdb9f2ff-95d4-4278-9d04-330f77625e13" xlink:to="loc_sitm_AuraMember_63357aaa-0897-45de-af65-b83c10873e02" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_21726fc8-1700-4cfc-8dec-7db69c1a028b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2cb07590-2ec5-441b-ac5c-ece14af734cf" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_21726fc8-1700-4cfc-8dec-7db69c1a028b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_5f60700b-e8b1-45ed-b9ee-0463a2878711" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_2cb07590-2ec5-441b-ac5c-ece14af734cf" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_5f60700b-e8b1-45ed-b9ee-0463a2878711" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/AcquisitionsScheduleofAcquisitionDateFairValueofthePurchaseConsiderationDetails" xlink:type="simple" xlink:href="sitm-20240930.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_e6abf050-be6e-4061-88ef-8ab9e2366a92" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_13ff9608-97d3-40cc-9797-9a28e584e08c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e6abf050-be6e-4061-88ef-8ab9e2366a92" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_13ff9608-97d3-40cc-9797-9a28e584e08c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_ba6e42dd-2489-49d9-a95e-7a1d8b20d981" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_13ff9608-97d3-40cc-9797-9a28e584e08c" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_ba6e42dd-2489-49d9-a95e-7a1d8b20d981" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ba6e42dd-2489-49d9-a95e-7a1d8b20d981_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_ba6e42dd-2489-49d9-a95e-7a1d8b20d981" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_ba6e42dd-2489-49d9-a95e-7a1d8b20d981_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_083095b7-f503-496e-a2a2-08c642c17cd9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_ba6e42dd-2489-49d9-a95e-7a1d8b20d981" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_083095b7-f503-496e-a2a2-08c642c17cd9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AuraMember_95d4db8b-b1b9-4df0-aa9a-4b972191f060" xlink:href="sitm-20240930.xsd#sitm_AuraMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_083095b7-f503-496e-a2a2-08c642c17cd9" xlink:to="loc_sitm_AuraMember_95d4db8b-b1b9-4df0-aa9a-4b972191f060" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_dce27da9-895a-4ffe-b6c7-7e24dc6ad399" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsToAcquireBusinessesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e6abf050-be6e-4061-88ef-8ab9e2366a92" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_dce27da9-895a-4ffe-b6c7-7e24dc6ad399" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred_acd166de-5f66-4713-974a-994e6d621cd4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e6abf050-be6e-4061-88ef-8ab9e2366a92" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred_acd166de-5f66-4713-974a-994e6d621cd4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_BusinessCombinationConsiderationTransferredSupplyAgreementSettlement_e9da7585-8776-4e85-a2b9-dec345bf2d29" xlink:href="sitm-20240930.xsd#sitm_BusinessCombinationConsiderationTransferredSupplyAgreementSettlement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e6abf050-be6e-4061-88ef-8ab9e2366a92" xlink:to="loc_sitm_BusinessCombinationConsiderationTransferredSupplyAgreementSettlement_e9da7585-8776-4e85-a2b9-dec345bf2d29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_7b4703f8-8db3-4339-80a8-13d470fafe77" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e6abf050-be6e-4061-88ef-8ab9e2366a92" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_7b4703f8-8db3-4339-80a8-13d470fafe77" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/AcquisitionsScheduleofAssetsAcquiredDetails" xlink:type="simple" xlink:href="sitm-20240930.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_8299ccb8-d06d-46b6-b086-9e7c724c6397" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_77d3ec4f-325b-4e0a-ab97-696314c47aea" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8299ccb8-d06d-46b6-b086-9e7c724c6397" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_77d3ec4f-325b-4e0a-ab97-696314c47aea" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_29f25381-0430-4919-a1c1-e97b19cdc9ca" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_77d3ec4f-325b-4e0a-ab97-696314c47aea" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_29f25381-0430-4919-a1c1-e97b19cdc9ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_29f25381-0430-4919-a1c1-e97b19cdc9ca_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_29f25381-0430-4919-a1c1-e97b19cdc9ca" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_29f25381-0430-4919-a1c1-e97b19cdc9ca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_045c336b-12cc-44ab-a01f-c5de987e78fc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_29f25381-0430-4919-a1c1-e97b19cdc9ca" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_045c336b-12cc-44ab-a01f-c5de987e78fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AuraMember_b4562146-6458-476c-853d-5570ecc132ec" xlink:href="sitm-20240930.xsd#sitm_AuraMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_045c336b-12cc-44ab-a01f-c5de987e78fc" xlink:to="loc_sitm_AuraMember_b4562146-6458-476c-853d-5570ecc132ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_93cc59fc-bd02-4083-b4c6-c60f16b8b7a4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_77d3ec4f-325b-4e0a-ab97-696314c47aea" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_93cc59fc-bd02-4083-b4c6-c60f16b8b7a4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_93cc59fc-bd02-4083-b4c6-c60f16b8b7a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_93cc59fc-bd02-4083-b4c6-c60f16b8b7a4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_93cc59fc-bd02-4083-b4c6-c60f16b8b7a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b4442421-30fc-4de3-8ae2-2a30072416c3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_93cc59fc-bd02-4083-b4c6-c60f16b8b7a4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b4442421-30fc-4de3-8ae2-2a30072416c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_2d584de7-83dd-4d45-a2ed-4f38df0da8f2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b4442421-30fc-4de3-8ae2-2a30072416c3" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_2d584de7-83dd-4d45-a2ed-4f38df0da8f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerContractsMember_989095d0-63c1-4276-8504-00eba7dc57a2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b4442421-30fc-4de3-8ae2-2a30072416c3" xlink:to="loc_us-gaap_CustomerContractsMember_989095d0-63c1-4276-8504-00eba7dc57a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_44cd4df3-f852-44c5-b971-bbd7bfad7580" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_77d3ec4f-325b-4e0a-ab97-696314c47aea" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_44cd4df3-f852-44c5-b971-bbd7bfad7580" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_44cd4df3-f852-44c5-b971-bbd7bfad7580_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_44cd4df3-f852-44c5-b971-bbd7bfad7580" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_44cd4df3-f852-44c5-b971-bbd7bfad7580_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_c0c75148-c70f-466b-ac0e-575030f38886" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_44cd4df3-f852-44c5-b971-bbd7bfad7580" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_c0c75148-c70f-466b-ac0e-575030f38886" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InProcessResearchAndDevelopmentMember_d14f12a5-da4d-407f-81db-5d44002b3fb1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InProcessResearchAndDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_c0c75148-c70f-466b-ac0e-575030f38886" xlink:to="loc_us-gaap_InProcessResearchAndDevelopmentMember_d14f12a5-da4d-407f-81db-5d44002b3fb1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_11dbcbec-2469-470a-a48a-2bf82d45e736" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_77d3ec4f-325b-4e0a-ab97-696314c47aea" xlink:to="loc_srt_RangeAxis_11dbcbec-2469-470a-a48a-2bf82d45e736" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_11dbcbec-2469-470a-a48a-2bf82d45e736_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_11dbcbec-2469-470a-a48a-2bf82d45e736" xlink:to="loc_srt_RangeMember_11dbcbec-2469-470a-a48a-2bf82d45e736_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_70fec780-804f-4726-a505-af8905b4eeb4" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_11dbcbec-2469-470a-a48a-2bf82d45e736" xlink:to="loc_srt_RangeMember_70fec780-804f-4726-a505-af8905b4eeb4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_335f5c1f-a646-479d-9bf2-633f44dbb387" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_70fec780-804f-4726-a505-af8905b4eeb4" xlink:to="loc_srt_MinimumMember_335f5c1f-a646-479d-9bf2-633f44dbb387" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_f185bfc4-e421-4074-b750-b6531f7e3016" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_70fec780-804f-4726-a505-af8905b4eeb4" xlink:to="loc_srt_MaximumMember_f185bfc4-e421-4074-b750-b6531f7e3016" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_1cf4257e-0d98-4bfc-b0ce-63d8027cfedb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8299ccb8-d06d-46b6-b086-9e7c724c6397" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_1cf4257e-0d98-4bfc-b0ce-63d8027cfedb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_547911e5-14a7-47fa-b9d7-5320fa28f986" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8299ccb8-d06d-46b6-b086-9e7c724c6397" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets_547911e5-14a7-47fa-b9d7-5320fa28f986" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_a52a24d4-bf91-42a4-a767-bcab797dfa89" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8299ccb8-d06d-46b6-b086-9e7c724c6397" xlink:to="loc_us-gaap_Goodwill_a52a24d4-bf91-42a4-a767-bcab797dfa89" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_c4fa24f7-5576-41bc-89f9-11d7f2486198" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8299ccb8-d06d-46b6-b086-9e7c724c6397" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_c4fa24f7-5576-41bc-89f9-11d7f2486198" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_1ccddd38-432c-4b86-9f6f-aef367991ce2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_8299ccb8-d06d-46b6-b086-9e7c724c6397" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_1ccddd38-432c-4b86-9f6f-aef367991ce2" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/AcquisitionsScheduleofProFormaInformationDetails" xlink:type="simple" xlink:href="sitm-20240930.xsd#AcquisitionsScheduleofProFormaInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/AcquisitionsScheduleofProFormaInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_a08589e0-0f71-4d6c-a065-483c040a1e13" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3fdcb41b-76f0-4054-9cbc-028b2b7ad9f1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_a08589e0-0f71-4d6c-a065-483c040a1e13" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3fdcb41b-76f0-4054-9cbc-028b2b7ad9f1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_95c042f0-a55a-4d06-a3f2-b6b6669e6767" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_3fdcb41b-76f0-4054-9cbc-028b2b7ad9f1" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_95c042f0-a55a-4d06-a3f2-b6b6669e6767" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_95c042f0-a55a-4d06-a3f2-b6b6669e6767_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_95c042f0-a55a-4d06-a3f2-b6b6669e6767" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_95c042f0-a55a-4d06-a3f2-b6b6669e6767_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d11382be-0e7e-4025-80a8-de9152ab5033" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_95c042f0-a55a-4d06-a3f2-b6b6669e6767" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d11382be-0e7e-4025-80a8-de9152ab5033" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AuraMember_49e1e878-4e1a-4bda-998a-ba95308c5909" xlink:href="sitm-20240930.xsd#sitm_AuraMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d11382be-0e7e-4025-80a8-de9152ab5033" xlink:to="loc_sitm_AuraMember_49e1e878-4e1a-4bda-998a-ba95308c5909" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_7349924c-4af9-4c30-bb90-fb0d7d1cb4fe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionsProFormaRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_a08589e0-0f71-4d6c-a065-483c040a1e13" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaRevenue_7349924c-4af9-4c30-bb90-fb0d7d1cb4fe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_f5b1f893-f970-4b84-b01b-b5de90d60af1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_a08589e0-0f71-4d6c-a065-483c040a1e13" xlink:to="loc_us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss_f5b1f893-f970-4b84-b01b-b5de90d60af1" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/FairValueMeasurementsAdditionalInformationDetails" xlink:type="simple" xlink:href="sitm-20240930.xsd#FairValueMeasurementsAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/FairValueMeasurementsAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b288d8e6-9414-4b7e-b5df-265808a70bca" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_07f14b89-8b58-463c-9ed5-7ba22a2c479b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b288d8e6-9414-4b7e-b5df-265808a70bca" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_07f14b89-8b58-463c-9ed5-7ba22a2c479b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_3ea12669-9ce7-4624-9f7f-ef862163a029" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_07f14b89-8b58-463c-9ed5-7ba22a2c479b" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_3ea12669-9ce7-4624-9f7f-ef862163a029" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3ea12669-9ce7-4624-9f7f-ef862163a029_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_3ea12669-9ce7-4624-9f7f-ef862163a029" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3ea12669-9ce7-4624-9f7f-ef862163a029_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_bb516dc9-7cf4-41bf-a343-99b824ad75f5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_3ea12669-9ce7-4624-9f7f-ef862163a029" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_bb516dc9-7cf4-41bf-a343-99b824ad75f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_b9d45b94-c9f0-4651-abd2-b5907d5f4809" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_bb516dc9-7cf4-41bf-a343-99b824ad75f5" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_b9d45b94-c9f0-4651-abd2-b5907d5f4809" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_d3073038-b375-45e3-8d2c-89f635257201" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_07f14b89-8b58-463c-9ed5-7ba22a2c479b" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_d3073038-b375-45e3-8d2c-89f635257201" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_d3073038-b375-45e3-8d2c-89f635257201_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_d3073038-b375-45e3-8d2c-89f635257201" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_d3073038-b375-45e3-8d2c-89f635257201_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_59c26040-3642-480c-a472-0ddbced20536" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_d3073038-b375-45e3-8d2c-89f635257201" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_59c26040-3642-480c-a472-0ddbced20536" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputPriceVolatilityMember_94dc0fef-63c1-48d0-a2a0-88b678b343e2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MeasurementInputPriceVolatilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_59c26040-3642-480c-a472-0ddbced20536" xlink:to="loc_us-gaap_MeasurementInputPriceVolatilityMember_94dc0fef-63c1-48d0-a2a0-88b678b343e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_daca9313-654c-4327-866f-a40912f47603" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_59c26040-3642-480c-a472-0ddbced20536" xlink:to="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_daca9313-654c-4327-866f-a40912f47603" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputExpectedTermMember_a3c5fba6-be97-49bf-a272-0e7bca8cafef" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MeasurementInputExpectedTermMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_59c26040-3642-480c-a472-0ddbced20536" xlink:to="loc_us-gaap_MeasurementInputExpectedTermMember_a3c5fba6-be97-49bf-a272-0e7bca8cafef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_652fbeb0-220f-4d44-9597-4f8e8f320357" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_07f14b89-8b58-463c-9ed5-7ba22a2c479b" xlink:to="loc_srt_RangeAxis_652fbeb0-220f-4d44-9597-4f8e8f320357" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_652fbeb0-220f-4d44-9597-4f8e8f320357_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_652fbeb0-220f-4d44-9597-4f8e8f320357" xlink:to="loc_srt_RangeMember_652fbeb0-220f-4d44-9597-4f8e8f320357_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3ad43cd0-1c5f-406f-9308-38cb1eab2c8b" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_652fbeb0-220f-4d44-9597-4f8e8f320357" xlink:to="loc_srt_RangeMember_3ad43cd0-1c5f-406f-9308-38cb1eab2c8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_d12c5333-134a-4673-9ab1-8f1e5e35a0b2" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3ad43cd0-1c5f-406f-9308-38cb1eab2c8b" xlink:to="loc_srt_MinimumMember_d12c5333-134a-4673-9ab1-8f1e5e35a0b2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_cef99eb9-735e-4429-9c41-28f7c64ac8f3" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3ad43cd0-1c5f-406f-9308-38cb1eab2c8b" xlink:to="loc_srt_MaximumMember_cef99eb9-735e-4429-9c41-28f7c64ac8f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsAtCarryingValue_d7db55e8-6cb3-49cc-9185-ac42e9b9a418" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MoneyMarketFundsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b288d8e6-9414-4b7e-b5df-265808a70bca" xlink:to="loc_us-gaap_MoneyMarketFundsAtCarryingValue_d7db55e8-6cb3-49cc-9185-ac42e9b9a418" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_TreasuryBillsMaturityDate_4f34a452-bab6-4fc8-83d0-3969ec435b4a" xlink:href="sitm-20240930.xsd#sitm_TreasuryBillsMaturityDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b288d8e6-9414-4b7e-b5df-265808a70bca" xlink:to="loc_sitm_TreasuryBillsMaturityDate_4f34a452-bab6-4fc8-83d0-3969ec435b4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_87f61d66-415f-4f4a-beaa-748b396cde0b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b288d8e6-9414-4b7e-b5df-265808a70bca" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestAfterAllowanceForCreditLoss_87f61d66-415f-4f4a-beaa-748b396cde0b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss_4226a114-54e1-436a-8a1c-4043320e61d9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b288d8e6-9414-4b7e-b5df-265808a70bca" xlink:to="loc_us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss_4226a114-54e1-436a-8a1c-4043320e61d9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesFairValue_4d4f0785-efd6-49eb-9cfb-56ce5d08d561" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HeldToMaturitySecuritiesFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b288d8e6-9414-4b7e-b5df-265808a70bca" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesFairValue_4d4f0785-efd6-49eb-9cfb-56ce5d08d561" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_734d057f-a6fa-4771-acb6-b6bea63d6736" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b288d8e6-9414-4b7e-b5df-265808a70bca" xlink:to="loc_us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_734d057f-a6fa-4771-acb6-b6bea63d6736" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput_972bdbe2-1365-45d2-ba6b-5bc68c426cb1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b288d8e6-9414-4b7e-b5df-265808a70bca" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityMeasurementInput_972bdbe2-1365-45d2-ba6b-5bc68c426cb1" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/BalanceSheetsComponentsScheduleofPropertyandEquipmentNetDetails" xlink:type="simple" xlink:href="sitm-20240930.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_ab8bf908-6494-4103-ada8-a11ea441b2a2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_b5497c6d-eb34-4edb-aece-4c5e8327951b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_ab8bf908-6494-4103-ada8-a11ea441b2a2" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_b5497c6d-eb34-4edb-aece-4c5e8327951b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_12129a3a-78ff-421e-987b-f46ae9a7864e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_b5497c6d-eb34-4edb-aece-4c5e8327951b" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_12129a3a-78ff-421e-987b-f46ae9a7864e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_12129a3a-78ff-421e-987b-f46ae9a7864e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_12129a3a-78ff-421e-987b-f46ae9a7864e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_12129a3a-78ff-421e-987b-f46ae9a7864e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_e0276f96-b33e-4c05-b80a-1d403bca23b6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_12129a3a-78ff-421e-987b-f46ae9a7864e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_e0276f96-b33e-4c05-b80a-1d403bca23b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LabAndManufacturingEquipmentMember_a5c41c78-606d-4c42-9e81-178689a0b0dc" xlink:href="sitm-20240930.xsd#sitm_LabAndManufacturingEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_e0276f96-b33e-4c05-b80a-1d403bca23b6" xlink:to="loc_sitm_LabAndManufacturingEquipmentMember_a5c41c78-606d-4c42-9e81-178689a0b0dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerEquipmentMember_fb79d313-85f3-4159-8927-48c28d189d53" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ComputerEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_e0276f96-b33e-4c05-b80a-1d403bca23b6" xlink:to="loc_us-gaap_ComputerEquipmentMember_fb79d313-85f3-4159-8927-48c28d189d53" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_8d8fd088-7214-4263-a591-70e7ae465889" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FurnitureAndFixturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_e0276f96-b33e-4c05-b80a-1d403bca23b6" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_8d8fd088-7214-4263-a591-70e7ae465889" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_c1fbed68-f46f-43b9-9c98-bae185208458" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_e0276f96-b33e-4c05-b80a-1d403bca23b6" xlink:to="loc_us-gaap_ConstructionInProgressMember_c1fbed68-f46f-43b9-9c98-bae185208458" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_29730acc-3be5-4a45-be78-a3b0a53b598e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_e0276f96-b33e-4c05-b80a-1d403bca23b6" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_29730acc-3be5-4a45-be78-a3b0a53b598e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_4fc5e265-55be-46a7-ba9a-76b32e7996ba" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_ab8bf908-6494-4103-ada8-a11ea441b2a2" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_4fc5e265-55be-46a7-ba9a-76b32e7996ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_c6a42f5a-921c-4031-8b54-35871b7728ee" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_ab8bf908-6494-4103-ada8-a11ea441b2a2" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_c6a42f5a-921c-4031-8b54-35871b7728ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_2401c661-6919-48ab-992f-0b87397877b4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_ab8bf908-6494-4103-ada8-a11ea441b2a2" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_2401c661-6919-48ab-992f-0b87397877b4" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/BalanceSheetsComponentsScheduleofIntangibleAssetsNetDetails" xlink:type="simple" xlink:href="sitm-20240930.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_39ab98d3-b328-48f9-9340-fcde5b1e5a26" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_b6342c61-9937-4a2d-8f3c-fbfd124dafe1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_39ab98d3-b328-48f9-9340-fcde5b1e5a26" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_b6342c61-9937-4a2d-8f3c-fbfd124dafe1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_11b6e80e-1679-4f43-b986-009f8e0810f2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_b6342c61-9937-4a2d-8f3c-fbfd124dafe1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_11b6e80e-1679-4f43-b986-009f8e0810f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_11b6e80e-1679-4f43-b986-009f8e0810f2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_11b6e80e-1679-4f43-b986-009f8e0810f2" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_11b6e80e-1679-4f43-b986-009f8e0810f2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b7d92b8d-b335-4ff6-b8c4-b6bd9278eab3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_11b6e80e-1679-4f43-b986-009f8e0810f2" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b7d92b8d-b335-4ff6-b8c4-b6bd9278eab3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_af5fbe8d-5b10-4554-ba3a-3347bc148270" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b7d92b8d-b335-4ff6-b8c4-b6bd9278eab3" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_af5fbe8d-5b10-4554-ba3a-3347bc148270" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractBasedIntangibleAssetsMember_8c120a4c-10b2-4899-b56e-75f20c00b409" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ContractBasedIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b7d92b8d-b335-4ff6-b8c4-b6bd9278eab3" xlink:to="loc_us-gaap_ContractBasedIntangibleAssetsMember_8c120a4c-10b2-4899-b56e-75f20c00b409" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_InternalUseSoftwareMember_f3afcff2-e8f1-453e-8b58-de51571b3c5d" xlink:href="sitm-20240930.xsd#sitm_InternalUseSoftwareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b7d92b8d-b335-4ff6-b8c4-b6bd9278eab3" xlink:to="loc_sitm_InternalUseSoftwareMember_f3afcff2-e8f1-453e-8b58-de51571b3c5d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PurchasedSoftwareMember_6e2b6c4c-2040-4370-8836-f904273ef580" xlink:href="sitm-20240930.xsd#sitm_PurchasedSoftwareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b7d92b8d-b335-4ff6-b8c4-b6bd9278eab3" xlink:to="loc_sitm_PurchasedSoftwareMember_6e2b6c4c-2040-4370-8836-f904273ef580" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_f92d0d40-5df4-42c1-8104-5fe02c6f49e0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_39ab98d3-b328-48f9-9340-fcde5b1e5a26" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_f92d0d40-5df4-42c1-8104-5fe02c6f49e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_988c008a-9c04-4e6f-ace1-2ac2c9399ad6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_39ab98d3-b328-48f9-9340-fcde5b1e5a26" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_988c008a-9c04-4e6f-ace1-2ac2c9399ad6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_1613ed3b-5323-45df-b184-4c3fe9fecdd7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_39ab98d3-b328-48f9-9340-fcde5b1e5a26" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_1613ed3b-5323-45df-b184-4c3fe9fecdd7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_8616154d-2cd0-4ad6-a02e-66d89021c2b0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_5204930a-6d8d-4334-88e2-f302e2407036" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_8616154d-2cd0-4ad6-a02e-66d89021c2b0" xlink:to="loc_us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_5204930a-6d8d-4334-88e2-f302e2407036" xlink:type="arc" order="2" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_04c47db6-1d31-4fed-8ad5-52a0d0b2e797" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_5204930a-6d8d-4334-88e2-f302e2407036" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_04c47db6-1d31-4fed-8ad5-52a0d0b2e797" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_04c47db6-1d31-4fed-8ad5-52a0d0b2e797_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_04c47db6-1d31-4fed-8ad5-52a0d0b2e797" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_04c47db6-1d31-4fed-8ad5-52a0d0b2e797_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_61e94801-6cf1-480c-9717-def106995ad6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_04c47db6-1d31-4fed-8ad5-52a0d0b2e797" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_61e94801-6cf1-480c-9717-def106995ad6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InProcessResearchAndDevelopmentMember_9c3d70bc-7649-4939-b674-bf634c816e6b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InProcessResearchAndDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_61e94801-6cf1-480c-9717-def106995ad6" xlink:to="loc_us-gaap_InProcessResearchAndDevelopmentMember_9c3d70bc-7649-4939-b674-bf634c816e6b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_8ce9d1d3-e8c2-4287-bf87-ae46a712a174" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_8616154d-2cd0-4ad6-a02e-66d89021c2b0" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_8ce9d1d3-e8c2-4287-bf87-ae46a712a174" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/LeasesAdditionalInformationDetails" xlink:type="simple" xlink:href="sitm-20240930.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_ebd29513-b1e5-42af-955d-9ee742364849" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionTable_16fee765-88f9-4b3e-9289-a8c5d815e148" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_ebd29513-b1e5-42af-955d-9ee742364849" xlink:to="loc_us-gaap_LessorLeaseDescriptionTable_16fee765-88f9-4b3e-9289-a8c5d815e148" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_922e9742-e0ed-4ebf-8e53-50dbd09b08bc" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_16fee765-88f9-4b3e-9289-a8c5d815e148" xlink:to="loc_srt_RangeAxis_922e9742-e0ed-4ebf-8e53-50dbd09b08bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_922e9742-e0ed-4ebf-8e53-50dbd09b08bc_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_922e9742-e0ed-4ebf-8e53-50dbd09b08bc" xlink:to="loc_srt_RangeMember_922e9742-e0ed-4ebf-8e53-50dbd09b08bc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_098b22bb-2a89-44cc-b79a-70445cfe90b5" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_922e9742-e0ed-4ebf-8e53-50dbd09b08bc" xlink:to="loc_srt_RangeMember_098b22bb-2a89-44cc-b79a-70445cfe90b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_b7e19416-b925-437a-a351-ffd73484c2f9" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_098b22bb-2a89-44cc-b79a-70445cfe90b5" xlink:to="loc_srt_MinimumMember_b7e19416-b925-437a-a351-ffd73484c2f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_f46530ce-a085-4ff8-bd9e-09dce6c51722" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_098b22bb-2a89-44cc-b79a-70445cfe90b5" xlink:to="loc_srt_MaximumMember_f46530ce-a085-4ff8-bd9e-09dce6c51722" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_356e48ba-1dbe-49e5-807c-6a1e709c1575" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_ebd29513-b1e5-42af-955d-9ee742364849" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_356e48ba-1dbe-49e5-807c-6a1e709c1575" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_8b7a2546-a33e-434f-8ee7-04b4768c6508" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_ebd29513-b1e5-42af-955d-9ee742364849" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_8b7a2546-a33e-434f-8ee7-04b4768c6508" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments_d22a6984-e4e9-4141-962e-614f15680a11" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeasePayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_ebd29513-b1e5-42af-955d-9ee742364849" xlink:to="loc_us-gaap_OperatingLeasePayments_d22a6984-e4e9-4141-962e-614f15680a11" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/StockholdersEquityAdditionalInformationDetails" xlink:type="simple" xlink:href="sitm-20240930.xsd#StockholdersEquityAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/StockholdersEquityAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a134cddf-7aef-4e48-9113-18c303bfbfa9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a134cddf-7aef-4e48-9113-18c303bfbfa9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_40026ced-fd8a-48ac-b246-c21df4647665" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a134cddf-7aef-4e48-9113-18c303bfbfa9" xlink:to="loc_us-gaap_TypeOfArrangementAxis_40026ced-fd8a-48ac-b246-c21df4647665" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_40026ced-fd8a-48ac-b246-c21df4647665_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_40026ced-fd8a-48ac-b246-c21df4647665" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_40026ced-fd8a-48ac-b246-c21df4647665_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_ca26fe94-e08a-452f-9f42-d4eabd8d6194" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_40026ced-fd8a-48ac-b246-c21df4647665" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_ca26fe94-e08a-452f-9f42-d4eabd8d6194" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AtTheMarketIssuanceSalesAgreementMember_efd12916-1824-4a77-8461-dc3fb654a954" xlink:href="sitm-20240930.xsd#sitm_AtTheMarketIssuanceSalesAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_ca26fe94-e08a-452f-9f42-d4eabd8d6194" xlink:to="loc_sitm_AtTheMarketIssuanceSalesAgreementMember_efd12916-1824-4a77-8461-dc3fb654a954" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_dadc8986-9835-45ea-b135-d9577a1c5520" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a134cddf-7aef-4e48-9113-18c303bfbfa9" xlink:to="loc_us-gaap_PlanNameAxis_dadc8986-9835-45ea-b135-d9577a1c5520" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_dadc8986-9835-45ea-b135-d9577a1c5520_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_dadc8986-9835-45ea-b135-d9577a1c5520" xlink:to="loc_us-gaap_PlanNameDomain_dadc8986-9835-45ea-b135-d9577a1c5520_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_f13914a1-dc95-4ffe-9f8e-73af4c5303ab" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_dadc8986-9835-45ea-b135-d9577a1c5520" xlink:to="loc_us-gaap_PlanNameDomain_f13914a1-dc95-4ffe-9f8e-73af4c5303ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_TwentyTwentyFourGoalsMember_18aa7430-cbaa-4510-bf27-fb4357f95989" xlink:href="sitm-20240930.xsd#sitm_TwentyTwentyFourGoalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_f13914a1-dc95-4ffe-9f8e-73af4c5303ab" xlink:to="loc_sitm_TwentyTwentyFourGoalsMember_18aa7430-cbaa-4510-bf27-fb4357f95989" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_0000e1a4-619d-4ffd-9370-598ed3d45f25" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a134cddf-7aef-4e48-9113-18c303bfbfa9" xlink:to="loc_us-gaap_AwardTypeAxis_0000e1a4-619d-4ffd-9370-598ed3d45f25" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0000e1a4-619d-4ffd-9370-598ed3d45f25_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_0000e1a4-619d-4ffd-9370-598ed3d45f25" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0000e1a4-619d-4ffd-9370-598ed3d45f25_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dfbd1a9c-e11a-4bac-856e-2bba8ba11655" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_0000e1a4-619d-4ffd-9370-598ed3d45f25" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dfbd1a9c-e11a-4bac-856e-2bba8ba11655" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_TotalStockholderPerformanceRestrictedStockUnitAwardMember_8ab84755-600f-492d-aae3-8b99d809efd1" xlink:href="sitm-20240930.xsd#sitm_TotalStockholderPerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dfbd1a9c-e11a-4bac-856e-2bba8ba11655" xlink:to="loc_sitm_TotalStockholderPerformanceRestrictedStockUnitAwardMember_8ab84755-600f-492d-aae3-8b99d809efd1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LiabilityBasedAwardMember_a9a6c289-6e17-4908-a1ad-2a4513b62178" xlink:href="sitm-20240930.xsd#sitm_LiabilityBasedAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dfbd1a9c-e11a-4bac-856e-2bba8ba11655" xlink:to="loc_sitm_LiabilityBasedAwardMember_a9a6c289-6e17-4908-a1ad-2a4513b62178" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_4f7b6eea-b436-417e-be9c-a021bd210508" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_a134cddf-7aef-4e48-9113-18c303bfbfa9" xlink:to="loc_srt_RangeAxis_4f7b6eea-b436-417e-be9c-a021bd210508" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_4f7b6eea-b436-417e-be9c-a021bd210508_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_4f7b6eea-b436-417e-be9c-a021bd210508" xlink:to="loc_srt_RangeMember_4f7b6eea-b436-417e-be9c-a021bd210508_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_53854235-df69-449e-a651-e87ead56ec78" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_4f7b6eea-b436-417e-be9c-a021bd210508" xlink:to="loc_srt_RangeMember_53854235-df69-449e-a651-e87ead56ec78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_0544f5b7-8824-4904-b327-0dacf0003cd2" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_53854235-df69-449e-a651-e87ead56ec78" xlink:to="loc_srt_MinimumMember_0544f5b7-8824-4904-b327-0dacf0003cd2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_9d6cfd54-d601-46fc-a69f-c60e4b218680" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_53854235-df69-449e-a651-e87ead56ec78" xlink:to="loc_srt_MaximumMember_9d6cfd54-d601-46fc-a69f-c60e4b218680" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_b1e68ef0-9757-4cba-b471-e561b909a65b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_b1e68ef0-9757-4cba-b471-e561b909a65b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_03bc0c80-2b66-4f5c-aa77-579ce80123bc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_03bc0c80-2b66-4f5c-aa77-579ce80123bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_c56e424d-debf-42f5-9fdf-e497da279820" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_c56e424d-debf-42f5-9fdf-e497da279820" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PercentageOfSalesCommissionFromCommonStockSold_1d6a211b-fde4-4bf3-bbc1-eea44404e007" xlink:href="sitm-20240930.xsd#sitm_PercentageOfSalesCommissionFromCommonStockSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_sitm_PercentageOfSalesCommissionFromCommonStockSold_1d6a211b-fde4-4bf3-bbc1-eea44404e007" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_SaleOfCommonStockPricePerShare_0236b15f-8fe3-41f8-99ae-dd584836d5a5" xlink:href="sitm-20240930.xsd#sitm_SaleOfCommonStockPricePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_sitm_SaleOfCommonStockPricePerShare_0236b15f-8fe3-41f8-99ae-dd584836d5a5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ProceedsFromIssuanceOfCommonStockNetOfUnderwritingDiscountsAndCommissions_b41005fa-d84c-4266-8cb6-7fb34d655d1e" xlink:href="sitm-20240930.xsd#sitm_ProceedsFromIssuanceOfCommonStockNetOfUnderwritingDiscountsAndCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_sitm_ProceedsFromIssuanceOfCommonStockNetOfUnderwritingDiscountsAndCommissions_b41005fa-d84c-4266-8cb6-7fb34d655d1e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PaymentsForUnderwritingDiscountsAndCommissions_3cd14ed0-3bae-4c15-be51-9bb72e8ecce6" xlink:href="sitm-20240930.xsd#sitm_PaymentsForUnderwritingDiscountsAndCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_sitm_PaymentsForUnderwritingDiscountsAndCommissions_3cd14ed0-3bae-4c15-be51-9bb72e8ecce6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfStockIssuanceCosts_f3ea40ff-4e58-4e34-aaf6-3fba4d8e43d9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsOfStockIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_us-gaap_PaymentsOfStockIssuanceCosts_f3ea40ff-4e58-4e34-aaf6-3fba4d8e43d9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AccruedExpensesAndOtherCurrentLiabilities_17f6a083-3b99-4dd5-a206-b99e8d005827" xlink:href="sitm-20240930.xsd#sitm_AccruedExpensesAndOtherCurrentLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_sitm_AccruedExpensesAndOtherCurrentLiabilities_17f6a083-3b99-4dd5-a206-b99e8d005827" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod_64151416-1cb5-4083-ba1f-264a1c35b069" xlink:href="sitm-20240930.xsd#sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod_64151416-1cb5-4083-ba1f-264a1c35b069" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_c7e60c0e-3f3f-4167-8eb0-e5e739bfc90e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_c7e60c0e-3f3f-4167-8eb0-e5e739bfc90e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_213dd66e-829b-4d21-b558-38cd25d6de18" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_213dd66e-829b-4d21-b558-38cd25d6de18" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_486d45ed-7b17-464b-9dbe-1ffae0fe8e13" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_486d45ed-7b17-464b-9dbe-1ffae0fe8e13" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_fa80bff8-272b-4ac2-9b9d-758ff8bf9085" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8c27d0a9-e3ad-4949-b714-22499358cfb0" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_fa80bff8-272b-4ac2-9b9d-758ff8bf9085" xlink:type="arc" order="13"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/StockholdersEquityScheduleofRestrictedStockUnitAwardRSUandPerformanceBasedRestrictedStockUnitAwardsPRSUandMultiyearPerformanceRestrictedStockUnitsMYPSUActivityDetails" xlink:type="simple" xlink:href="sitm-20240930.xsd#StockholdersEquityScheduleofRestrictedStockUnitAwardRSUandPerformanceBasedRestrictedStockUnitAwardsPRSUandMultiyearPerformanceRestrictedStockUnitsMYPSUActivityDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/StockholdersEquityScheduleofRestrictedStockUnitAwardRSUandPerformanceBasedRestrictedStockUnitAwardsPRSUandMultiyearPerformanceRestrictedStockUnitsMYPSUActivityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_21fc9e83-59ba-40c5-98ad-21da28ea7cc3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2a13a249-77be-47cc-b2d4-f6e6b03cd946" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_21fc9e83-59ba-40c5-98ad-21da28ea7cc3" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2a13a249-77be-47cc-b2d4-f6e6b03cd946" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_455f233c-36c3-49eb-8047-62ed3f8051ae" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2a13a249-77be-47cc-b2d4-f6e6b03cd946" xlink:to="loc_us-gaap_AwardTypeAxis_455f233c-36c3-49eb-8047-62ed3f8051ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_455f233c-36c3-49eb-8047-62ed3f8051ae_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_455f233c-36c3-49eb-8047-62ed3f8051ae" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_455f233c-36c3-49eb-8047-62ed3f8051ae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10ee9691-3818-4b7f-af38-31b7fed96c17" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_455f233c-36c3-49eb-8047-62ed3f8051ae" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10ee9691-3818-4b7f-af38-31b7fed96c17" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_74495ace-e1cb-4fcb-b6aa-af537bac0dee" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10ee9691-3818-4b7f-af38-31b7fed96c17" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_74495ace-e1cb-4fcb-b6aa-af537bac0dee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PerformanceRestrictedStockUnitAwardMember_b7b19b6d-9259-4e34-b3c7-7550029a1b93" xlink:href="sitm-20240930.xsd#sitm_PerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10ee9691-3818-4b7f-af38-31b7fed96c17" xlink:to="loc_sitm_PerformanceRestrictedStockUnitAwardMember_b7b19b6d-9259-4e34-b3c7-7550029a1b93" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_cdf43ccc-c823-4af0-b3f0-ef4cf11270fd" xlink:href="sitm-20240930.xsd#sitm_MultiYearPerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_10ee9691-3818-4b7f-af38-31b7fed96c17" xlink:to="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_cdf43ccc-c823-4af0-b3f0-ef4cf11270fd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d69985ee-42fc-4fbc-b672-ccd4e20c42d5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_21fc9e83-59ba-40c5-98ad-21da28ea7cc3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d69985ee-42fc-4fbc-b672-ccd4e20c42d5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_47f21210-f4b1-4c3f-a36a-daf4508b5647" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d69985ee-42fc-4fbc-b672-ccd4e20c42d5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_47f21210-f4b1-4c3f-a36a-daf4508b5647" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_5cfa3623-ca9f-404d-8d90-b6303f39527a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d69985ee-42fc-4fbc-b672-ccd4e20c42d5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_5cfa3623-ca9f-404d-8d90-b6303f39527a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_34bf094c-04d2-4a25-857f-fb4b47763108" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d69985ee-42fc-4fbc-b672-ccd4e20c42d5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_34bf094c-04d2-4a25-857f-fb4b47763108" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_e1259915-32be-4579-950c-617da9cf61da" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d69985ee-42fc-4fbc-b672-ccd4e20c42d5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_e1259915-32be-4579-950c-617da9cf61da" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_c1a6834a-1639-46e7-9dbb-7df726dedd4b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_647e4e41-6a60-4b02-b165-4b1a151074e8" xlink:href="sitm-20240930.xsd#sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_21fc9e83-59ba-40c5-98ad-21da28ea7cc3" xlink:to="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_647e4e41-6a60-4b02-b165-4b1a151074e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_8475859a-4b70-4428-ac3e-b2da6ec6cf87" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_647e4e41-6a60-4b02-b165-4b1a151074e8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_8475859a-4b70-4428-ac3e-b2da6ec6cf87" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_5290250c-dcc9-4d21-b62d-1504e7c0a493" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_647e4e41-6a60-4b02-b165-4b1a151074e8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_5290250c-dcc9-4d21-b62d-1504e7c0a493" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_1e4fc384-d409-4377-a96d-e6b8fe886496" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_647e4e41-6a60-4b02-b165-4b1a151074e8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_1e4fc384-d409-4377-a96d-e6b8fe886496" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_08636fe0-6f65-48c6-be3c-fd9651187105" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_sitm_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRFRollForward_647e4e41-6a60-4b02-b165-4b1a151074e8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_08636fe0-6f65-48c6-be3c-fd9651187105" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_2e45cfbf-0392-40fc-b242-0ab8b081c9a1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/StockholdersEquityScheduleofStockbasedCompensationExpenseAmountsIncludedinCondensedConsolidatedStatementofOperationsDetails" xlink:type="simple" xlink:href="sitm-20240930.xsd#StockholdersEquityScheduleofStockbasedCompensationExpenseAmountsIncludedinCondensedConsolidatedStatementofOperationsDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/StockholdersEquityScheduleofStockbasedCompensationExpenseAmountsIncludedinCondensedConsolidatedStatementofOperationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4062c461-d266-42de-b880-3a4140f67956" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_28821c93-3dcd-4b16-8409-69cc75fc1d40" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4062c461-d266-42de-b880-3a4140f67956" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_28821c93-3dcd-4b16-8409-69cc75fc1d40" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_4af7302f-6921-4d52-bb80-380da3a42739" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_28821c93-3dcd-4b16-8409-69cc75fc1d40" xlink:to="loc_us-gaap_AwardTypeAxis_4af7302f-6921-4d52-bb80-380da3a42739" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4af7302f-6921-4d52-bb80-380da3a42739_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_4af7302f-6921-4d52-bb80-380da3a42739" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4af7302f-6921-4d52-bb80-380da3a42739_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09ddc1bd-5dae-4b64-9a87-080726657db7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_4af7302f-6921-4d52-bb80-380da3a42739" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09ddc1bd-5dae-4b64-9a87-080726657db7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_EquityAwardMember_a6359dac-beb1-4e42-afb4-dc96aaec721a" xlink:href="sitm-20240930.xsd#sitm_EquityAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09ddc1bd-5dae-4b64-9a87-080726657db7" xlink:to="loc_sitm_EquityAwardMember_a6359dac-beb1-4e42-afb4-dc96aaec721a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LiabilityBasedAwardsToBeSettledInEquityMember_60ea556f-71ab-4e01-8bfb-635dfe629a8f" xlink:href="sitm-20240930.xsd#sitm_LiabilityBasedAwardsToBeSettledInEquityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09ddc1bd-5dae-4b64-9a87-080726657db7" xlink:to="loc_sitm_LiabilityBasedAwardsToBeSettledInEquityMember_60ea556f-71ab-4e01-8bfb-635dfe629a8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_EquityAndLiabilityBasedAwardsMember_c473925f-213f-4cb7-b62e-8750cf376339" xlink:href="sitm-20240930.xsd#sitm_EquityAndLiabilityBasedAwardsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09ddc1bd-5dae-4b64-9a87-080726657db7" xlink:to="loc_sitm_EquityAndLiabilityBasedAwardsMember_c473925f-213f-4cb7-b62e-8750cf376339" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LiabilityBasedAwardMember_0b6b4704-f9e3-4e39-85f9-4c845a6ccd63" xlink:href="sitm-20240930.xsd#sitm_LiabilityBasedAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_09ddc1bd-5dae-4b64-9a87-080726657db7" xlink:to="loc_sitm_LiabilityBasedAwardMember_0b6b4704-f9e3-4e39-85f9-4c845a6ccd63" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_bd95cbe8-0c67-421e-8dc0-9156626ecff7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_28821c93-3dcd-4b16-8409-69cc75fc1d40" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_bd95cbe8-0c67-421e-8dc0-9156626ecff7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_bd95cbe8-0c67-421e-8dc0-9156626ecff7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_bd95cbe8-0c67-421e-8dc0-9156626ecff7" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_bd95cbe8-0c67-421e-8dc0-9156626ecff7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_9ee8c3c1-1a38-4e6f-9d4a-bc3b07c17ba9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_bd95cbe8-0c67-421e-8dc0-9156626ecff7" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_9ee8c3c1-1a38-4e6f-9d4a-bc3b07c17ba9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_c8545dee-5ab8-49c0-abe7-743bf0f5112f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9ee8c3c1-1a38-4e6f-9d4a-bc3b07c17ba9" xlink:to="loc_us-gaap_CostOfSalesMember_c8545dee-5ab8-49c0-abe7-743bf0f5112f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_34602596-9a60-4c52-ba8b-4727623eb3a4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9ee8c3c1-1a38-4e6f-9d4a-bc3b07c17ba9" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_34602596-9a60-4c52-ba8b-4727623eb3a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_35b17b58-f64b-4743-99bc-28e3b14ce610" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9ee8c3c1-1a38-4e6f-9d4a-bc3b07c17ba9" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_35b17b58-f64b-4743-99bc-28e3b14ce610" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_534dc8a1-c2d6-4a9f-8189-b55329cfb86e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_28821c93-3dcd-4b16-8409-69cc75fc1d40" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_534dc8a1-c2d6-4a9f-8189-b55329cfb86e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_534dc8a1-c2d6-4a9f-8189-b55329cfb86e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_534dc8a1-c2d6-4a9f-8189-b55329cfb86e" xlink:to="loc_us-gaap_EquityComponentDomain_534dc8a1-c2d6-4a9f-8189-b55329cfb86e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_709a5e70-c083-4d46-b650-84bc4b4db056" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_534dc8a1-c2d6-4a9f-8189-b55329cfb86e" xlink:to="loc_us-gaap_EquityComponentDomain_709a5e70-c083-4d46-b650-84bc4b4db056" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_6c814de5-135b-4a69-ab46-3ae5812bc0a3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_709a5e70-c083-4d46-b650-84bc4b4db056" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_6c814de5-135b-4a69-ab46-3ae5812bc0a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_c48ea7cd-94a3-4dd5-80c2-a9ca55016f99" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4062c461-d266-42de-b880-3a4140f67956" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_c48ea7cd-94a3-4dd5-80c2-a9ca55016f99" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount_50f39eef-ca73-42af-abf7-5f169dbb8538" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4062c461-d266-42de-b880-3a4140f67956" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount_50f39eef-ca73-42af-abf7-5f169dbb8538" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1_3872909f-5cb0-432e-bae7-cd5929edc1ca" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4062c461-d266-42de-b880-3a4140f67956" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardCompensationCost1_3872909f-5cb0-432e-bae7-cd5929edc1ca" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/StockholdersEquityScheduleofUnrecognizedCompensationCostsandRelatedWeightedAveragePeriodofRecognitionDetails" xlink:type="simple" xlink:href="sitm-20240930.xsd#StockholdersEquityScheduleofUnrecognizedCompensationCostsandRelatedWeightedAveragePeriodofRecognitionDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/StockholdersEquityScheduleofUnrecognizedCompensationCostsandRelatedWeightedAveragePeriodofRecognitionDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34f7d430-6626-4340-9c9e-d0705f3e7c6c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5543a3b7-03a6-44b7-a25e-441b1b74b3af" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34f7d430-6626-4340-9c9e-d0705f3e7c6c" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5543a3b7-03a6-44b7-a25e-441b1b74b3af" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_2ed10c44-1ca2-41b2-8cb7-ef0af729da15" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5543a3b7-03a6-44b7-a25e-441b1b74b3af" xlink:to="loc_us-gaap_AwardTypeAxis_2ed10c44-1ca2-41b2-8cb7-ef0af729da15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2ed10c44-1ca2-41b2-8cb7-ef0af729da15_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_2ed10c44-1ca2-41b2-8cb7-ef0af729da15" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2ed10c44-1ca2-41b2-8cb7-ef0af729da15_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eb416acc-65cb-4e3a-9b89-81b6e609f4dd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_2ed10c44-1ca2-41b2-8cb7-ef0af729da15" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eb416acc-65cb-4e3a-9b89-81b6e609f4dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_efdd1cde-2a98-4895-bb5f-b32d30427701" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eb416acc-65cb-4e3a-9b89-81b6e609f4dd" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_efdd1cde-2a98-4895-bb5f-b32d30427701" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PhantomShareUnitsPSUsMember_521c4a9f-3389-4063-86f7-e5e856fac661" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PhantomShareUnitsPSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eb416acc-65cb-4e3a-9b89-81b6e609f4dd" xlink:to="loc_us-gaap_PhantomShareUnitsPSUsMember_521c4a9f-3389-4063-86f7-e5e856fac661" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_c5546d78-d5d0-4ac4-84fd-04d8f7d38113" xlink:href="sitm-20240930.xsd#sitm_MultiYearPerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eb416acc-65cb-4e3a-9b89-81b6e609f4dd" xlink:to="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_c5546d78-d5d0-4ac4-84fd-04d8f7d38113" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LiabilityBasedAwardMember_5e52a67b-4f97-4e7a-8d1e-9f13bf766405" xlink:href="sitm-20240930.xsd#sitm_LiabilityBasedAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eb416acc-65cb-4e3a-9b89-81b6e609f4dd" xlink:to="loc_sitm_LiabilityBasedAwardMember_5e52a67b-4f97-4e7a-8d1e-9f13bf766405" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_66c6ace4-5982-4c89-b1a0-3d02bdb3716e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34f7d430-6626-4340-9c9e-d0705f3e7c6c" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_66c6ace4-5982-4c89-b1a0-3d02bdb3716e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_53630bb3-d011-4f59-9a56-58d6f499241c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34f7d430-6626-4340-9c9e-d0705f3e7c6c" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_53630bb3-d011-4f59-9a56-58d6f499241c" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/IncomeTaxesAdditionalInformationDetails" xlink:type="simple" xlink:href="sitm-20240930.xsd#IncomeTaxesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/IncomeTaxesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxHolidayLineItems_915fd1ac-39ff-4900-a02e-09e8f9c65afe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxHolidayLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxHolidayTable_71aa9799-8223-4804-a6b3-e933cd5df5c0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxHolidayTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxHolidayLineItems_915fd1ac-39ff-4900-a02e-09e8f9c65afe" xlink:to="loc_us-gaap_IncomeTaxHolidayTable_71aa9799-8223-4804-a6b3-e933cd5df5c0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e8f87495-0db4-4699-8cfe-35a281cc8b88" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxHolidayTable_71aa9799-8223-4804-a6b3-e933cd5df5c0" xlink:to="loc_srt_RangeAxis_e8f87495-0db4-4699-8cfe-35a281cc8b88" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e8f87495-0db4-4699-8cfe-35a281cc8b88_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e8f87495-0db4-4699-8cfe-35a281cc8b88" xlink:to="loc_srt_RangeMember_e8f87495-0db4-4699-8cfe-35a281cc8b88_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2995a648-8914-4a5d-8a5f-78e81e228c78" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e8f87495-0db4-4699-8cfe-35a281cc8b88" xlink:to="loc_srt_RangeMember_2995a648-8914-4a5d-8a5f-78e81e228c78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_85d9b35c-47ff-4556-959b-ce5a712fa16a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2995a648-8914-4a5d-8a5f-78e81e228c78" xlink:to="loc_srt_MaximumMember_85d9b35c-47ff-4556-959b-ce5a712fa16a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_efbe1b92-9df9-494c-a169-a95a1793a107" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxHolidayLineItems_915fd1ac-39ff-4900-a02e-09e8f9c65afe" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_efbe1b92-9df9-494c-a169-a95a1793a107" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_58e27ca9-fa37-4bc6-ad64-f9946020d169" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxHolidayLineItems_915fd1ac-39ff-4900-a02e-09e8f9c65afe" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_58e27ca9-fa37-4bc6-ad64-f9946020d169" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_9731e15a-c80e-4602-8d95-b64c4f94a1ec" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxHolidayLineItems_915fd1ac-39ff-4900-a02e-09e8f9c65afe" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_9731e15a-c80e-4602-8d95-b64c4f94a1ec" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefits_4f099d01-dad5-4ade-ac23-ad95a99d6c98" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_UnrecognizedTaxBenefits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxHolidayLineItems_915fd1ac-39ff-4900-a02e-09e8f9c65afe" xlink:to="loc_us-gaap_UnrecognizedTaxBenefits_4f099d01-dad5-4ade-ac23-ad95a99d6c98" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/SegmentGeographicandCustomerInformationScheduleofRevenuebyCountryDetails" xlink:type="simple" xlink:href="sitm-20240930.xsd#SegmentGeographicandCustomerInformationScheduleofRevenuebyCountryDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/SegmentGeographicandCustomerInformationScheduleofRevenuebyCountryDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_72457385-c83c-4bb5-bc09-c945c53ebc9f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ca4781ca-338f-4831-b87c-2713ba2f4f78" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_72457385-c83c-4bb5-bc09-c945c53ebc9f" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ca4781ca-338f-4831-b87c-2713ba2f4f78" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_910d6104-f179-4390-9036-7d6153136244" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ca4781ca-338f-4831-b87c-2713ba2f4f78" xlink:to="loc_srt_StatementGeographicalAxis_910d6104-f179-4390-9036-7d6153136244" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_910d6104-f179-4390-9036-7d6153136244_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_910d6104-f179-4390-9036-7d6153136244" xlink:to="loc_srt_SegmentGeographicalDomain_910d6104-f179-4390-9036-7d6153136244_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_d1b1c4e9-71f9-4dea-8b33-5b35bb6995da" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_910d6104-f179-4390-9036-7d6153136244" xlink:to="loc_srt_SegmentGeographicalDomain_d1b1c4e9-71f9-4dea-8b33-5b35bb6995da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_TW_3efc673a-70b4-413a-a785-b701641f83e8" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_TW"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_d1b1c4e9-71f9-4dea-8b33-5b35bb6995da" xlink:to="loc_country_TW_3efc673a-70b4-413a-a785-b701641f83e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_HK_de7ce990-45dd-4da6-b520-d2872cc99fcb" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_HK"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_d1b1c4e9-71f9-4dea-8b33-5b35bb6995da" xlink:to="loc_country_HK_de7ce990-45dd-4da6-b520-d2872cc99fcb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_9e9dbc1f-0f78-4654-bb53-ddc37227db69" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_d1b1c4e9-71f9-4dea-8b33-5b35bb6995da" xlink:to="loc_country_US_9e9dbc1f-0f78-4654-bb53-ddc37227db69" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_SG_5c467cc6-43c7-494f-8db5-efbb1785819d" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_SG"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_d1b1c4e9-71f9-4dea-8b33-5b35bb6995da" xlink:to="loc_country_SG_5c467cc6-43c7-494f-8db5-efbb1785819d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_OtherCountriesMember_a7f97fd9-06ec-4511-84f6-45340d435aca" xlink:href="sitm-20240930.xsd#sitm_OtherCountriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_d1b1c4e9-71f9-4dea-8b33-5b35bb6995da" xlink:to="loc_sitm_OtherCountriesMember_a7f97fd9-06ec-4511-84f6-45340d435aca" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_8104a0ec-0275-4360-8ae5-ae95e35c588c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ca4781ca-338f-4831-b87c-2713ba2f4f78" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_8104a0ec-0275-4360-8ae5-ae95e35c588c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_8104a0ec-0275-4360-8ae5-ae95e35c588c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_8104a0ec-0275-4360-8ae5-ae95e35c588c" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_8104a0ec-0275-4360-8ae5-ae95e35c588c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_a0ce48a6-3e09-4315-b5aa-a08271c5d4e9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_8104a0ec-0275-4360-8ae5-ae95e35c588c" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_a0ce48a6-3e09-4315-b5aa-a08271c5d4e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_034a986c-ced5-4368-bfdf-7195cebbce98" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_a0ce48a6-3e09-4315-b5aa-a08271c5d4e9" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_034a986c-ced5-4368-bfdf-7195cebbce98" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_bbe1e04d-6e6a-40f6-8303-06e01adfecee" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ca4781ca-338f-4831-b87c-2713ba2f4f78" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_bbe1e04d-6e6a-40f6-8303-06e01adfecee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_bbe1e04d-6e6a-40f6-8303-06e01adfecee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_bbe1e04d-6e6a-40f6-8303-06e01adfecee" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_bbe1e04d-6e6a-40f6-8303-06e01adfecee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_65eca4de-a8b1-48ab-a6b4-a364b14819a6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_bbe1e04d-6e6a-40f6-8303-06e01adfecee" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_65eca4de-a8b1-48ab-a6b4-a364b14819a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicConcentrationRiskMember_70c9d446-5cb4-4244-bc59-c003b48d4611" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GeographicConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_65eca4de-a8b1-48ab-a6b4-a364b14819a6" xlink:to="loc_us-gaap_GeographicConcentrationRiskMember_70c9d446-5cb4-4244-bc59-c003b48d4611" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_70be6031-7008-4844-b2b5-5672f5247e5c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_72457385-c83c-4bb5-bc09-c945c53ebc9f" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_70be6031-7008-4844-b2b5-5672f5247e5c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.sitime.com/role/SegmentGeographicandCustomerInformationScheduleofPropertyandEquipmentAttributabletoOperationsDetails" xlink:type="simple" xlink:href="sitm-20240930.xsd#SegmentGeographicandCustomerInformationScheduleofPropertyandEquipmentAttributabletoOperationsDetails"/>
  <link:definitionLink xlink:role="http://www.sitime.com/role/SegmentGeographicandCustomerInformationScheduleofPropertyandEquipmentAttributabletoOperationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_c88d729e-45e7-435f-942a-94982f186867" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5ed2b9cb-197e-421a-81ea-ec63d132c09d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c88d729e-45e7-435f-942a-94982f186867" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5ed2b9cb-197e-421a-81ea-ec63d132c09d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_1e884007-bf53-4639-b053-6b146a32df62" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5ed2b9cb-197e-421a-81ea-ec63d132c09d" xlink:to="loc_srt_StatementGeographicalAxis_1e884007-bf53-4639-b053-6b146a32df62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_1e884007-bf53-4639-b053-6b146a32df62_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_1e884007-bf53-4639-b053-6b146a32df62" xlink:to="loc_srt_SegmentGeographicalDomain_1e884007-bf53-4639-b053-6b146a32df62_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_0725e17f-2b85-44f4-8c08-0c43411ad256" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_1e884007-bf53-4639-b053-6b146a32df62" xlink:to="loc_srt_SegmentGeographicalDomain_0725e17f-2b85-44f4-8c08-0c43411ad256" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_249b8b2d-baef-440d-9f92-1b0f87a04b19" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_0725e17f-2b85-44f4-8c08-0c43411ad256" xlink:to="loc_country_US_249b8b2d-baef-440d-9f92-1b0f87a04b19" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_MY_77a8257f-2458-43b0-95cc-f33c0699b372" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_MY"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_0725e17f-2b85-44f4-8c08-0c43411ad256" xlink:to="loc_country_MY_77a8257f-2458-43b0-95cc-f33c0699b372" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_TW_a8dd8e48-65e9-4d5f-a928-834d80590f45" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_TW"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_0725e17f-2b85-44f4-8c08-0c43411ad256" xlink:to="loc_country_TW_a8dd8e48-65e9-4d5f-a928-834d80590f45" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_OtherCountriesMember_fc9d4e9f-7c0b-4473-899d-ce7e9a605029" xlink:href="sitm-20240930.xsd#sitm_OtherCountriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_0725e17f-2b85-44f4-8c08-0c43411ad256" xlink:to="loc_sitm_OtherCountriesMember_fc9d4e9f-7c0b-4473-899d-ce7e9a605029" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_05646252-12d5-46b9-a5f4-844458a5ab81" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_c88d729e-45e7-435f-942a-94982f186867" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_05646252-12d5-46b9-a5f4-844458a5ab81" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2024/ecd-2024.xsd#AwardTypeOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PerformanceRestrictedStockUnitAwardMember_3f761739-b058-4e07-819e-51239bbae528" xlink:href="sitm-20240930.xsd#sitm_PerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_sitm_PerformanceRestrictedStockUnitAwardMember_3f761739-b058-4e07-819e-51239bbae528" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_3f9e87f1-7773-458b-94d2-04a80462073d" xlink:href="sitm-20240930.xsd#sitm_MultiYearPerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_sitm_MultiYearPerformanceRestrictedStockUnitAwardMember_3f9e87f1-7773-458b-94d2-04a80462073d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_TotalStockholderPerformanceRestrictedStockUnitAwardMember_6eb1d29c-2794-41c6-bb9f-9ea4e00ebbde" xlink:href="sitm-20240930.xsd#sitm_TotalStockholderPerformanceRestrictedStockUnitAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_sitm_TotalStockholderPerformanceRestrictedStockUnitAwardMember_6eb1d29c-2794-41c6-bb9f-9ea4e00ebbde" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LiabilityBasedAwardMember_cf7ecd71-f29b-4be2-a3b6-a000d8e9a9cc" xlink:href="sitm-20240930.xsd#sitm_LiabilityBasedAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_sitm_LiabilityBasedAwardMember_cf7ecd71-f29b-4be2-a3b6-a000d8e9a9cc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_EquityAwardMember_038b3f27-35e2-4662-8dc9-fceb89dcf300" xlink:href="sitm-20240930.xsd#sitm_EquityAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_sitm_EquityAwardMember_038b3f27-35e2-4662-8dc9-fceb89dcf300" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LiabilityBasedAwardsToBeSettledInEquityMember_520b882c-3c5b-4a5d-82e5-91bac8059941" xlink:href="sitm-20240930.xsd#sitm_LiabilityBasedAwardsToBeSettledInEquityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_sitm_LiabilityBasedAwardsToBeSettledInEquityMember_520b882c-3c5b-4a5d-82e5-91bac8059941" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_EquityAndLiabilityBasedAwardsMember_960f300f-3ab9-4e14-887a-c1341993326e" xlink:href="sitm-20240930.xsd#sitm_EquityAndLiabilityBasedAwardsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_sitm_EquityAndLiabilityBasedAwardsMember_960f300f-3ab9-4e14-887a-c1341993326e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PhantomShareUnitsPSUsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PhantomShareUnitsPSUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_PhantomShareUnitsPSUsMember" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2024/ecd-2024.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/2024/ecd-2024.xsd#ecd_AllIndividualsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_RajeshVashistMember_5c6effaa-935d-4d63-b492-f4630ce715b2" xlink:href="sitm-20240930.xsd#sitm_RajeshVashistMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_sitm_RajeshVashistMember_5c6effaa-935d-4d63-b492-f4630ce715b2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_KatherineSchuelkeMember_8b81b671-f9e6-46c6-98f8-98df5390d7fc" xlink:href="sitm-20240930.xsd#sitm_KatherineSchuelkeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_sitm_KatherineSchuelkeMember_8b81b671-f9e6-46c6-98f8-98df5390d7fc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_LionelBonnotMember_267dea3e-b57e-47ed-9a2e-fc651ab22f37" xlink:href="sitm-20240930.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_267dea3e-b57e-47ed-9a2e-fc651ab22f37" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_PiyushSevaliaMember_dfd872cd-5c39-4491-af86-f2b04af56c6c" xlink:href="sitm-20240930.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_dfd872cd-5c39-4491-af86-f2b04af56c6c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_VincentPangrazioMember_7eb43da6-3c43-4d49-af72-d772505d4ebf" xlink:href="sitm-20240930.xsd#sitm_VincentPangrazioMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_sitm_VincentPangrazioMember_7eb43da6-3c43-4d49-af72-d772505d4ebf" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-roles-2024.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_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_sitm_AccruedExpensesAndOtherCurrentLiabilities_1d207fc3-8c38-4d85-a3bc-a498b0747c01" xlink:href="sitm-20240930.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_1d207fc3-8c38-4d85-a3bc-a498b0747c01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.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="1"/>
  </link:definitionLink>
</link:linkbase>
