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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019fcdb6-12ef-7f87-a7dc-deab46ef6611,g:dc2a8764-b4d2-48c0-9a1f-0e4dbfa72e17-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:dxcm="http://www.dexcom.com/20260930" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.dexcom.com/20260930">
  <xs:import namespace="http://fasb.org/srt/2026" schemaLocation="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2026" schemaLocation="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/country/2026" schemaLocation="https://xbrl.sec.gov/country/2026/country-2026.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2026" schemaLocation="https://xbrl.sec.gov/dei/2026/dei-2026.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2026" schemaLocation="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="dxcm-20260930_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="dxcm-20260930_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="dxcm-20260930_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="dxcm-20260930_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="Cover" roleURI="http://www.dexcom.com/role/Cover">
        <link:definition>0000001 - Document - Cover</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedBalanceSheets" roleURI="http://www.dexcom.com/role/CondensedConsolidatedBalanceSheets">
        <link:definition>9952151 - Statement - Condensed Consolidated Balance Sheets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedBalanceSheetsParenthetical" roleURI="http://www.dexcom.com/role/CondensedConsolidatedBalanceSheetsParenthetical">
        <link:definition>9952152 - Statement - Condensed Consolidated Balance Sheets (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofOperations" roleURI="http://www.dexcom.com/role/CondensedConsolidatedStatementsofOperations">
        <link:definition>9952153 - Statement - Condensed Consolidated Statements of Operations</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofComprehensiveIncome" roleURI="http://www.dexcom.com/role/CondensedConsolidatedStatementsofComprehensiveIncome">
        <link:definition>9952154 - Statement - Condensed Consolidated Statements of Comprehensive Income</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofStockholdersEquity" roleURI="http://www.dexcom.com/role/CondensedConsolidatedStatementsofStockholdersEquity">
        <link:definition>9952155 - Statement - Condensed Consolidated Statements of Stockholders' Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CondensedConsolidatedStatementsofCashFlows" roleURI="http://www.dexcom.com/role/CondensedConsolidatedStatementsofCashFlows">
        <link:definition>9952156 - Statement - Condensed Consolidated Statements of Cash Flows</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OrganizationandSignificantAccountingPolicies" roleURI="http://www.dexcom.com/role/OrganizationandSignificantAccountingPolicies">
        <link:definition>9952157 - Disclosure - Organization and Significant Accounting Policies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurements" roleURI="http://www.dexcom.com/role/FairValueMeasurements">
        <link:definition>9952158 - Disclosure - Fair Value Measurements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformation" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformation">
        <link:definition>9952159 - Disclosure - Balance Sheet Details and Other Financial Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Debt" roleURI="http://www.dexcom.com/role/Debt">
        <link:definition>9952160 - Disclosure - Debt</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Contingencies" roleURI="http://www.dexcom.com/role/Contingencies">
        <link:definition>9952161 - Disclosure - Contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxes" roleURI="http://www.dexcom.com/role/IncomeTaxes">
        <link:definition>9952162 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquity" roleURI="http://www.dexcom.com/role/StockholdersEquity">
        <link:definition>9952163 - Disclosure - Stockholders' Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BusinessSegmentandGeographicInformation" roleURI="http://www.dexcom.com/role/BusinessSegmentandGeographicInformation">
        <link:definition>9952164 - Disclosure - Business Segment and Geographic Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SubsequentEvents" roleURI="http://www.dexcom.com/role/SubsequentEvents">
        <link:definition>9952165 - Disclosure - Subsequent Events</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OrganizationandSignificantAccountingPoliciesPolicies" roleURI="http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesPolicies">
        <link:definition>9955511 - Disclosure - Organization and Significant Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OrganizationandSignificantAccountingPoliciesTables" roleURI="http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesTables">
        <link:definition>9955512 - Disclosure - Organization and Significant Accounting Policies (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsTables" roleURI="http://www.dexcom.com/role/FairValueMeasurementsTables">
        <link:definition>9955513 - Disclosure - Fair Value Measurements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationTables" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationTables">
        <link:definition>9955514 - Disclosure - Balance Sheet Details and Other Financial Information (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtTables" roleURI="http://www.dexcom.com/role/DebtTables">
        <link:definition>9955515 - Disclosure - Debt (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityTables" roleURI="http://www.dexcom.com/role/StockholdersEquityTables">
        <link:definition>9955516 - Disclosure - Stockholders' Equity (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BusinessSegmentandGeographicInformationTables" roleURI="http://www.dexcom.com/role/BusinessSegmentandGeographicInformationTables">
        <link:definition>9955517 - Disclosure - Business Segment and Geographic Information (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OrganizationandSignificantAccountingPoliciesNarrativeDetails" roleURI="http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesNarrativeDetails">
        <link:definition>9955518 - Disclosure - Organization and Significant Accounting Policies - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OrganizationandSignificantAccountingPoliciesScheduleofBasicandDilutedNetIncomeperShareDetails" roleURI="http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesScheduleofBasicandDilutedNetIncomeperShareDetails">
        <link:definition>9955519 - Disclosure - Organization and Significant Accounting Policies - Schedule of Basic and Diluted Net Income per Share (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OrganizationandSignificantAccountingPoliciesScheduleofOutstandingAntidilutiveSecuritiesExcludedfromDilutedNetIncomeperShareDetails" roleURI="http://www.dexcom.com/role/OrganizationandSignificantAccountingPoliciesScheduleofOutstandingAntidilutiveSecuritiesExcludedfromDilutedNetIncomeperShareDetails">
        <link:definition>9955520 - Disclosure - Organization and Significant Accounting Policies - Schedule of Outstanding Anti-dilutive Securities Excluded from Diluted Net Income per Share (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsScheduleofFairValueHierarchyforFinancialAssetsDetails" roleURI="http://www.dexcom.com/role/FairValueMeasurementsScheduleofFairValueHierarchyforFinancialAssetsDetails">
        <link:definition>9955521 - Disclosure - Fair Value Measurements - Schedule of Fair Value Hierarchy for Financial Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsNarrativeDetails" roleURI="http://www.dexcom.com/role/FairValueMeasurementsNarrativeDetails">
        <link:definition>9955522 - Disclosure - Fair Value Measurements - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationShortTermDebtsMarketableSecuritiesDetails" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationShortTermDebtsMarketableSecuritiesDetails">
        <link:definition>9955523 - Disclosure - Balance Sheet Details and Other Financial Information - Short-Term Debts Marketable Securities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationNarrativeDetails" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationNarrativeDetails">
        <link:definition>9955524 - Disclosure - Balance Sheet Details and Other Financial Information - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationNarrativeDetails_1" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationNarrativeDetails_1">
        <link:definition>9955524 - Disclosure - Balance Sheet Details and Other Financial Information - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationInventoryDetails" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationInventoryDetails">
        <link:definition>9955525 - Disclosure - Balance Sheet Details and Other Financial Information - Inventory (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationPrepaidandOtherCurrentAssetsDetails" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationPrepaidandOtherCurrentAssetsDetails">
        <link:definition>9955526 - Disclosure - Balance Sheet Details and Other Financial Information - Prepaid and Other Current Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationPropertyandEquipmentDetails" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationPropertyandEquipmentDetails">
        <link:definition>9955527 - Disclosure - Balance Sheet Details and Other Financial Information - Property and Equipment (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationOtherAssetsDetails" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationOtherAssetsDetails">
        <link:definition>9955528 - Disclosure - Balance Sheet Details and Other Financial Information - Other Assets (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationAccountsPayableandAccruedLiabilitiesDetails" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationAccountsPayableandAccruedLiabilitiesDetails">
        <link:definition>9955529 - Disclosure - Balance Sheet Details and Other Financial Information - Accounts Payable and Accrued Liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationAccruedPayrollandRelatedExpensesDetails" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationAccruedPayrollandRelatedExpensesDetails">
        <link:definition>9955530 - Disclosure - Balance Sheet Details and Other Financial Information - Accrued Payroll and Related Expenses (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationOtherLongTermLiabilitiesDetails" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationOtherLongTermLiabilitiesDetails">
        <link:definition>9955531 - Disclosure - Balance Sheet Details and Other Financial Information - Other Long-Term Liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BalanceSheetDetailsandOtherFinancialInformationOtherIncomeNetDetails" roleURI="http://www.dexcom.com/role/BalanceSheetDetailsandOtherFinancialInformationOtherIncomeNetDetails">
        <link:definition>9955532 - Disclosure - Balance Sheet Details and Other Financial Information - Other Income, Net (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtSeniorConvertibleNotesDetails" roleURI="http://www.dexcom.com/role/DebtSeniorConvertibleNotesDetails">
        <link:definition>9955533 - Disclosure - Debt - Senior Convertible Notes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtScheduleofCarryingValuesandEstimatedFairValuesofDebtInstrumentsDetails" roleURI="http://www.dexcom.com/role/DebtScheduleofCarryingValuesandEstimatedFairValuesofDebtInstrumentsDetails">
        <link:definition>9955534 - Disclosure - Debt - Schedule of Carrying Values and Estimated Fair Values of Debt Instruments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtScheduleofComponentsofInterestExpenseandEffectiveInterestRatesofSeniorConvertibleNotesDetails" roleURI="http://www.dexcom.com/role/DebtScheduleofComponentsofInterestExpenseandEffectiveInterestRatesofSeniorConvertibleNotesDetails">
        <link:definition>9955535 - Disclosure - Debt - Schedule of Components of Interest Expense and Effective Interest Rates of Senior Convertible Notes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtScheduleofEstimatedFairValuesofDebtInstrumentsDetails" roleURI="http://www.dexcom.com/role/DebtScheduleofEstimatedFairValuesofDebtInstrumentsDetails">
        <link:definition>9955536 - Disclosure - Debt - Schedule of Estimated Fair Values of Debt Instruments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtScheduleofKeyDetailsofConvertibleNotesDetails" roleURI="http://www.dexcom.com/role/DebtScheduleofKeyDetailsofConvertibleNotesDetails">
        <link:definition>9955537 - Disclosure - Debt - Schedule of Key Details of Convertible Notes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Debt2028CappedCallTransactionsDetails" roleURI="http://www.dexcom.com/role/Debt2028CappedCallTransactionsDetails">
        <link:definition>9955538 - Disclosure - Debt - 2028 Capped Call Transactions (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtConversionRightsforSeniorsConvertibleNotesDetails" roleURI="http://www.dexcom.com/role/DebtConversionRightsforSeniorsConvertibleNotesDetails">
        <link:definition>9955539 - Disclosure - Debt - Conversion Rights for Seniors Convertible Notes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtCreditAgreementDetails" roleURI="http://www.dexcom.com/role/DebtCreditAgreementDetails">
        <link:definition>9955540 - Disclosure - Debt - Credit Agreement (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxesDetails" roleURI="http://www.dexcom.com/role/IncomeTaxesDetails">
        <link:definition>9955541 - Disclosure - Income Taxes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityScheduleofShareBasedCompensationExpenseDetails" roleURI="http://www.dexcom.com/role/StockholdersEquityScheduleofShareBasedCompensationExpenseDetails">
        <link:definition>9955542 - Disclosure - Stockholders' Equity - Schedule of Share-Based Compensation Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityScheduleofShareBasedCompensationExpenseDetails_1" roleURI="http://www.dexcom.com/role/StockholdersEquityScheduleofShareBasedCompensationExpenseDetails_1">
        <link:definition>9955542 - Disclosure - Stockholders' Equity - Schedule of Share-Based Compensation Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityNarrativeDetails" roleURI="http://www.dexcom.com/role/StockholdersEquityNarrativeDetails">
        <link:definition>9955543 - Disclosure - Stockholders' Equity - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BusinessSegmentandGeographicInformationNarrativeDetails" roleURI="http://www.dexcom.com/role/BusinessSegmentandGeographicInformationNarrativeDetails">
        <link:definition>9955544 - Disclosure - Business Segment and Geographic Information - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BusinessSegmentandGeographicInformationScheduleofSegmentInformationDetails" roleURI="http://www.dexcom.com/role/BusinessSegmentandGeographicInformationScheduleofSegmentInformationDetails">
        <link:definition>9955545 - Disclosure - Business Segment and Geographic Information - Schedule of Segment Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="BusinessSegmentandGeographicInformationScheduleofDisaggregationofRevenueDetails" roleURI="http://www.dexcom.com/role/BusinessSegmentandGeographicInformationScheduleofDisaggregationofRevenueDetails">
        <link:definition>9955546 - Disclosure - Business Segment and Geographic Information - Schedule of Disaggregation of Revenue (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SubsequentEventsDetails" roleURI="http://www.dexcom.com/role/SubsequentEventsDetails">
        <link:definition>9955547 - Disclosure - Subsequent Events (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="dxcm_DebtSecuritiesAvailableForSaleExcludingAccruedInterestAndEquitySecurities" abstract="false" name="DebtSecuritiesAvailableForSaleExcludingAccruedInterestAndEquitySecurities" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_IncreaseDecreaseInOperatingLeaseAssetsAndLiabilitiesNet" abstract="false" name="IncreaseDecreaseInOperatingLeaseAssetsAndLiabilitiesNet" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiabilityNet" abstract="false" name="RightOfUseAssetObtainedInExchangeForOperatingLeaseLiabilityNet" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_PrepaidAndOtherCurrentAssetsTableTextBlock" abstract="false" name="PrepaidAndOtherCurrentAssetsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="dxcm_ScheduleOfAccruedPayrollAndRelatedExpensesTableTextBlock" abstract="false" name="ScheduleOfAccruedPayrollAndRelatedExpensesTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="dxcm_OrganizationAndSummaryOfSignificantAccountingPoliciesTable" abstract="true" name="OrganizationAndSummaryOfSignificantAccountingPoliciesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="dxcm_OrganizationAndSummaryOfSignificantAccountingPoliciesLineItems" abstract="true" name="OrganizationAndSummaryOfSignificantAccountingPoliciesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="dxcm_ContractPaymentTermsNumberOfDays" abstract="false" name="ContractPaymentTermsNumberOfDays" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="dxcm_RestrictedAndPerformanceStockUnitsMember" abstract="true" name="RestrictedAndPerformanceStockUnitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_AlternativeInvestmentMeasurementAlternativeMember" abstract="true" name="AlternativeInvestmentMeasurementAlternativeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_FairValueAssetsLevel3TransfersAmount" abstract="false" name="FairValueAssetsLevel3TransfersAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_AcquiredTechnologyAndIntellectualPropertyMember" abstract="true" name="AcquiredTechnologyAndIntellectualPropertyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_DeferredCompensationPlanAssetsCurrent" abstract="false" name="DeferredCompensationPlanAssetsCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_IndirectTaxReceivablesCurrent" abstract="false" name="IndirectTaxReceivablesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_LongTermDeposits" abstract="false" name="LongTermDeposits" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_OtherLongTermAssets" abstract="false" name="OtherLongTermAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_PharmacyRebatesCurrent" abstract="false" name="PharmacyRebatesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_AccruedTaxAuditAndLegalFees" abstract="false" name="AccruedTaxAuditAndLegalFees" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_AccruedWagesBonusesAndTaxesCurrent" abstract="false" name="AccruedWagesBonusesAndTaxesCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_OtherTaxLiabilitiesNoncurrent" abstract="false" name="OtherTaxLiabilitiesNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_ConvertibleNotesDue2025Member" abstract="true" name="ConvertibleNotesDue2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_ConvertibleNotesDue2028Member" abstract="true" name="ConvertibleNotesDue2028Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_CashInterestExpenseAbstract" abstract="true" name="CashInterestExpenseAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="dxcm_NonCashInterestExpenseAbstract" abstract="true" name="NonCashInterestExpenseAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="dxcm_FairValueDisclosuresTable" abstract="true" name="FairValueDisclosuresTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="dxcm_FairValueDisclosuresLineItems" abstract="true" name="FairValueDisclosuresLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="dxcm_DebtInstrumentCapCallTransactionCapPricePerShare" abstract="false" name="DebtInstrumentCapCallTransactionCapPricePerShare" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="dxcm_DebtInstrumentConvertibleCappedCallsInitialCapPricePremiumPercentage" abstract="false" name="DebtInstrumentConvertibleCappedCallsInitialCapPricePremiumPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="dxcm_PaymentsForPurchasesOfCappedCallTransactions" abstract="false" name="PaymentsForPurchasesOfCappedCallTransactions" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_ConvertibleNotesDue2023Member" abstract="true" name="ConvertibleNotesDue2023Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_DebtInstrumentConversionTermAxis" abstract="true" name="DebtInstrumentConversionTermAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="dxcm_DebtInstrumentConversionTermDomain" abstract="true" name="DebtInstrumentConversionTermDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_DebtInstrumentConversionTermOneMember" abstract="true" name="DebtInstrumentConversionTermOneMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_DebtInstrumentConversionTermTwoMember" abstract="true" name="DebtInstrumentConversionTermTwoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_DebtInstrumentCovenantRepurchasePricePercentage" abstract="false" name="DebtInstrumentCovenantRepurchasePricePercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="dxcm_DebtInstrumentRedemptionCovenantPercentOfConversionPriceLastReportedSalePriceOfCommonStock" abstract="false" name="DebtInstrumentRedemptionCovenantPercentOfConversionPriceLastReportedSalePriceOfCommonStock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="dxcm_CreditAgreementMember" abstract="true" name="CreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_LineOfCreditFacilityAccordionFeaturePercentageOfEBITDA" abstract="false" name="LineOfCreditFacilityAccordionFeaturePercentageOfEBITDA" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="dxcm_EstimatedAnnualEffectiveIncomeTaxRatePercent" abstract="false" name="EstimatedAnnualEffectiveIncomeTaxRatePercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="dxcm_RestrictedStockUnitsRSUsAndPerformanceSharesMember" abstract="true" name="RestrictedStockUnitsRSUsAndPerformanceSharesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_EquityIncentivePlan2015Member" abstract="true" name="EquityIncentivePlan2015Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_A2025ShareRepurchaseProgramMember" abstract="true" name="A2025ShareRepurchaseProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_A2026ShareRepurchaseProgramMember" abstract="true" name="A2026ShareRepurchaseProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_NumberOfPrimaryGeographicMarkets" abstract="false" name="NumberOfPrimaryGeographicMarkets" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="dxcm_ReportableSegmentMember" abstract="true" name="ReportableSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_PayrollRelatedExpenses" abstract="false" name="PayrollRelatedExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_ShareBasedPaymentArrangementOperatingExpense" abstract="false" name="ShareBasedPaymentArrangementOperatingExpense" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_SupplyExpensesAndClinicalTrials" abstract="false" name="SupplyExpensesAndClinicalTrials" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_EquipmentOfficeAndFacilityExpenses" abstract="false" name="EquipmentOfficeAndFacilityExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="dxcm_A2027ShareRepurchaseProgramMember" abstract="true" name="A2027ShareRepurchaseProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="dxcm_KyleMaladyMember" abstract="true" name="KyleMaladyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
