<?xml version="1.0" encoding="us-ascii"?>
<!-- DFIN ActiveDisclosure(SM) XBRL Schema Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date      : 2020-05-07T17:48:14.9959377+00:00 -->
<!-- Version            : 5.0.1.385 -->
<!-- Package ID         : 3b8c8e386706441eb7d66a80ae4b92ba -->
<!-- Copyright (c) 2020 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<xsd:schema xmlns:nonnum="http://www.xbrl.org/dtr/type/non-numeric" xmlns:num="http://www.xbrl.org/dtr/type/numeric" xmlns:sic="http://xbrl.sec.gov/sic/2011-01-31" xmlns:stpr="http://xbrl.sec.gov/stpr/2018-01-31" xmlns:naics="http://xbrl.sec.gov/naics/2017-01-31" xmlns:srt-types="http://fasb.org/srt-types/2019-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:srt="http://fasb.org/srt/2019-01-31" xmlns:nsit="http://www.insight.com/20200331" xmlns:us-gaap="http://fasb.org/us-gaap/2019-01-31" xmlns:dei="http://xbrl.sec.gov/dei/2019-01-31" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:country="http://xbrl.sec.gov/country/2017-01-31" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:currency="http://xbrl.sec.gov/currency/2019-01-31" xmlns:us-types="http://fasb.org/us-types/2019-01-31" xmlns:exch="http://xbrl.sec.gov/exch/2019-01-31" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.insight.com/20200331" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/instance" />
  <xsd:import schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" namespace="http://www.xbrl.org/2003/linkbase" />
  <xsd:import schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" namespace="http://xbrl.org/2005/xbrldt" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/country/2017/country-2017-01-31.xsd" namespace="http://xbrl.sec.gov/country/2017-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/currency/2019/currency-2019-01-31.xsd" namespace="http://xbrl.sec.gov/currency/2019-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/dei/2019/dei-2019-01-31.xsd" namespace="http://xbrl.sec.gov/dei/2019-01-31" />
  <xsd:import schemaLocation="http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd" namespace="http://www.xbrl.org/dtr/type/non-numeric" />
  <xsd:import schemaLocation="http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd" namespace="http://www.xbrl.org/dtr/type/numeric" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/exch/2019/exch-2019-01-31.xsd" namespace="http://xbrl.sec.gov/exch/2019-01-31" />
  <xsd:import schemaLocation="http://www.xbrl.org/lrr/arcrole/factExplanatory-2009-12-16.xsd" namespace="http://www.xbrl.org/2009/arcrole/fact-explanatoryFact" />
  <xsd:import schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd" namespace="http://www.xbrl.org/2009/role/negated" />
  <xsd:import schemaLocation="http://www.xbrl.org/lrr/role/net-2009-12-16.xsd" namespace="http://www.xbrl.org/2009/role/net" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/naics/2017/naics-2017-01-31.xsd" namespace="http://xbrl.sec.gov/naics/2017-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/sic/2011/sic-2011-01-31.xsd" namespace="http://xbrl.sec.gov/sic/2011-01-31" />
  <xsd:import schemaLocation="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd" namespace="http://fasb.org/srt/2019-01-31" />
  <xsd:import schemaLocation="http://xbrl.fasb.org/srt/2019/elts/srt-roles-2019-01-31.xsd" namespace="http://fasb.org/srt-roles/2019-01-31" />
  <xsd:import schemaLocation="http://xbrl.fasb.org/srt/2019/elts/srt-types-2019-01-31.xsd" namespace="http://fasb.org/srt-types/2019-01-31" />
  <xsd:import schemaLocation="https://xbrl.sec.gov/stpr/2018/stpr-2018-01-31.xsd" namespace="http://xbrl.sec.gov/stpr/2018-01-31" />
  <xsd:import schemaLocation="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd" namespace="http://fasb.org/us-gaap/2019-01-31" />
  <xsd:import schemaLocation="http://xbrl.fasb.org/us-gaap/2019/elts/us-roles-2019-01-31.xsd" namespace="http://fasb.org/us-roles/2019-01-31" />
  <xsd:import schemaLocation="http://xbrl.fasb.org/us-gaap/2019/elts/us-types-2019-01-31.xsd" namespace="http://fasb.org/us-types/2019-01-31" />
  <xsd:annotation>
    <xsd:appinfo>
      <link:roleType id="TemplateLink" roleURI="http://www.insight.com/20200331/role/TemplateLink" xmlns:link="http://www.xbrl.org/2003/linkbase">
        <link:definition>00000 - Document - Template Link</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="nsit-20200331_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:title="Calculation Links, all" xlink:type="simple" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="nsit-20200331_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:title="Definition Links, all" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="nsit-20200331_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:title="Label Links, all" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="nsit-20200331_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:title="Presentation Links, all" xlink:type="simple" />
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DocumentDocumentAndEntityInformation" id="Role_DocumentDocumentAndEntityInformation">
        <link:definition>100000 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/StatementConsolidatedBalanceSheetsUnaudited" id="Role_StatementConsolidatedBalanceSheetsUnaudited">
        <link:definition>100010 - Statement - Consolidated Balance Sheets (unaudited)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/StatementConsolidatedBalanceSheetsUnauditedParenthetical" id="Role_StatementConsolidatedBalanceSheetsUnauditedParenthetical">
        <link:definition>100020 - Statement - Consolidated Balance Sheets (unaudited) (Parenthetical)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/StatementConsolidatedStatementsOfOperationsUnaudited" id="Role_StatementConsolidatedStatementsOfOperationsUnaudited">
        <link:definition>100030 - Statement - Consolidated Statements of Operations (unaudited)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/StatementConsolidatedStatementsOfComprehensiveIncomeUnaudited" id="Role_StatementConsolidatedStatementsOfComprehensiveIncomeUnaudited">
        <link:definition>100040 - Statement - Consolidated Statements of Comprehensive Income (unaudited)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/StatementConsolidatedStatementsOfStockholdersEquityUnaudited" id="Role_StatementConsolidatedStatementsOfStockholdersEquityUnaudited">
        <link:definition>100050 - Statement - Consolidated Statements of Stockholders&apos; Equity (unaudited)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/StatementConsolidatedStatementsOfCashFlowsUnaudited" id="Role_StatementConsolidatedStatementsOfCashFlowsUnaudited">
        <link:definition>100060 - Statement - Consolidated Statements of Cash Flows (unaudited)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureBasisOfPresentationAndRecentlyIssuedAccountingStandards" id="Role_DisclosureBasisOfPresentationAndRecentlyIssuedAccountingStandards">
        <link:definition>100070 - Disclosure - Basis of Presentation and Recently Issued Accounting Standards</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSalesRecognition" id="Role_DisclosureSalesRecognition">
        <link:definition>100080 - Disclosure - Sales Recognition</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureAssetsHeldForSale" id="Role_DisclosureAssetsHeldForSale">
        <link:definition>100090 - Disclosure - Assets Held for Sale</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureNetEarningsPerShareEPS" id="Role_DisclosureNetEarningsPerShareEPS">
        <link:definition>100100 - Disclosure - Net Earnings Per Share ("EPS")</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureDebtInventoryFinancingFacilityFinanceLeasesAndOtherFinancingObligations" id="Role_DisclosureDebtInventoryFinancingFacilityFinanceLeasesAndOtherFinancingObligations">
        <link:definition>100110 - Disclosure - Debt, Inventory Financing Facility, Finance Leases and Other Financing Obligations</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureLeases" id="Role_DisclosureLeases">
        <link:definition>100120 - Disclosure - Leases</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureStockBasedCompensation" id="Role_DisclosureStockBasedCompensation">
        <link:definition>100130 - Disclosure - Stock-Based Compensation</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureIncomeTaxes" id="Role_DisclosureIncomeTaxes">
        <link:definition>100140 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureShareRepurchaseProgram" id="Role_DisclosureShareRepurchaseProgram">
        <link:definition>100150 - Disclosure - Share Repurchase Program</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureCommitmentsAndContingencies" id="Role_DisclosureCommitmentsAndContingencies">
        <link:definition>100160 - Disclosure - Commitments and Contingencies</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSegmentInformation" id="Role_DisclosureSegmentInformation">
        <link:definition>100170 - Disclosure - Segment Information</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureAcquisitions" id="Role_DisclosureAcquisitions">
        <link:definition>100180 - Disclosure - Acquisitions</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSubsequentEvent" id="Role_DisclosureSubsequentEvent">
        <link:definition>100190 - Disclosure - Subsequent Event</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureBasisOfPresentationAndRecentlyIssuedAccountingStandardsPolicies" id="Role_DisclosureBasisOfPresentationAndRecentlyIssuedAccountingStandardsPolicies">
        <link:definition>100200 - Disclosure - Basis of Presentation and Recently Issued Accounting Standards (Policies)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSalesRecognitionTables" id="Role_DisclosureSalesRecognitionTables">
        <link:definition>100210 - Disclosure - Sales Recognition (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureNetEarningsPerShareEPSTables" id="Role_DisclosureNetEarningsPerShareEPSTables">
        <link:definition>100220 - Disclosure - Net Earnings Per Share ("EPS") (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureDebtInventoryFinancingFacilitiesFinanceLeasesAndOtherFinancingObligationsTables" id="Role_DisclosureDebtInventoryFinancingFacilitiesFinanceLeasesAndOtherFinancingObligationsTables">
        <link:definition>100230 - Disclosure - Debt, Inventory Financing Facilities, Finance Leases and Other Financing Obligations (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureLeasesTables" id="Role_DisclosureLeasesTables">
        <link:definition>100240 - Disclosure - Leases (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureStockBasedCompensationTables" id="Role_DisclosureStockBasedCompensationTables">
        <link:definition>100250 - Disclosure - Stock-Based Compensation (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSegmentInformationTables" id="Role_DisclosureSegmentInformationTables">
        <link:definition>100260 - Disclosure - Segment Information (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureAcquisitionsTables" id="Role_DisclosureAcquisitionsTables">
        <link:definition>100270 - Disclosure - Acquisitions (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureBasisOfPresentationAndRecentlyIssuedAccountingStandardsAdditionalInformationDetail" id="Role_DisclosureBasisOfPresentationAndRecentlyIssuedAccountingStandardsAdditionalInformationDetail">
        <link:definition>100280 - Disclosure - Basis of Presentation and Recently Issued Accounting Standards - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSalesRecognitionSummaryOfRevenueDisaggregatedByReportableOperatingSegmentsDetail" id="Role_DisclosureSalesRecognitionSummaryOfRevenueDisaggregatedByReportableOperatingSegmentsDetail">
        <link:definition>100290 - Disclosure - Sales Recognition - Summary of Revenue Disaggregated by Reportable Operating Segments (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSalesRecognitionSummaryOfInformationAboutReceivablesAndContractLiabilitiesDetail" id="Role_DisclosureSalesRecognitionSummaryOfInformationAboutReceivablesAndContractLiabilitiesDetail">
        <link:definition>100300 - Disclosure - Sales Recognition - Summary of Information about Receivables and Contract Liabilities (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSalesRecognitionSummaryOfChangesInContractLiabilitiesFromContractWithCustomersDetail" id="Role_DisclosureSalesRecognitionSummaryOfChangesInContractLiabilitiesFromContractWithCustomersDetail">
        <link:definition>100310 - Disclosure - Sales Recognition - Summary of Changes in Contract Liabilities from Contract with Customers (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSalesRecognitionSummaryOfEstimatedNetSalesRelatedToPerformanceObligationDetail" id="Role_DisclosureSalesRecognitionSummaryOfEstimatedNetSalesRelatedToPerformanceObligationDetail">
        <link:definition>100320 - Disclosure - Sales Recognition - Summary of Estimated Net Sales Related to Performance Obligation (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSalesRecognitionSummaryOfEstimatedNetSalesRelatedToPerformanceObligationDetailDefault" id="Role_DisclosureSalesRecognitionSummaryOfEstimatedNetSalesRelatedToPerformanceObligationDetailDefault">
        <link:definition>100320 - Disclosure - Sales Recognition - Summary of Estimated Net Sales Related to Performance Obligation (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSalesRecognitionSummaryOfEstimatedNetSalesRelatedToPerformanceObligationDetail1" id="Role_DisclosureSalesRecognitionSummaryOfEstimatedNetSalesRelatedToPerformanceObligationDetail1">
        <link:definition>100330 - Disclosure - Sales Recognition - Summary of Estimated Net Sales Related to Performance Obligation (Detail 1)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSalesRecognitionAdditionalInformationDetail" id="Role_DisclosureSalesRecognitionAdditionalInformationDetail">
        <link:definition>100340 - Disclosure - Sales Recognition - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureAssetsHeldForSaleAdditionalInformationDetail" id="Role_DisclosureAssetsHeldForSaleAdditionalInformationDetail">
        <link:definition>100350 - Disclosure - Assets Held for Sale - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureNetEarningsPerShareEPSReconciliationOfDenominatorsOfBasicAndDilutedEPSCalculationsDetail" id="Role_DisclosureNetEarningsPerShareEPSReconciliationOfDenominatorsOfBasicAndDilutedEPSCalculationsDetail">
        <link:definition>100360 - Disclosure - Net Earnings Per Share ("EPS") - Reconciliation of Denominators of Basic and Diluted EPS Calculations (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureNetEarningsPerShareEPSAdditionalInformationDetail" id="Role_DisclosureNetEarningsPerShareEPSAdditionalInformationDetail">
        <link:definition>100370 - Disclosure - Net Earnings Per Share ("EPS") - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureDebtInventoryFinancingFacilitiesFinanceLeasesAndOtherFinancingObligationsLongTermDebtDetail" id="Role_DisclosureDebtInventoryFinancingFacilitiesFinanceLeasesAndOtherFinancingObligationsLongTermDebtDetail">
        <link:definition>100380 - Disclosure - Debt, Inventory Financing Facilities, Finance Leases and Other Financing Obligations - Long-Term Debt (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureDebtInventoryFinancingFacilitiesFinanceLeasesAndOtherFinancingObligationsLongTermDebtDetail2" id="Role_DisclosureDebtInventoryFinancingFacilitiesFinanceLeasesAndOtherFinancingObligationsLongTermDebtDetail2">
        <link:definition>100390 - Disclosure - Debt, Inventory Financing Facilities, Finance Leases and Other Financing Obligations - Long-Term Debt (Detail)2</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureDebtInventoryFinancingFacilitiesFinanceLeasesAndOtherFinancingObligationsAdditionalInformationDetail" id="Role_DisclosureDebtInventoryFinancingFacilitiesFinanceLeasesAndOtherFinancingObligationsAdditionalInformationDetail">
        <link:definition>100400 - Disclosure - Debt, Inventory Financing Facilities, Finance Leases and Other Financing Obligations - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureDebtInventoryFinancingFacilitiesFinanceLeasesAndOtherFinancingObligationsScheduleOfConvertibleSeniorNotesBalancesDetail" id="Role_DisclosureDebtInventoryFinancingFacilitiesFinanceLeasesAndOtherFinancingObligationsScheduleOfConvertibleSeniorNotesBalancesDetail">
        <link:definition>100410 - Disclosure - Debt, Inventory Financing Facilities, Finance Leases and Other Financing Obligations - Schedule of Convertible Senior Notes Balances (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureLeasesAdditionalInformationDetail" id="Role_DisclosureLeasesAdditionalInformationDetail">
        <link:definition>100420 - Disclosure - Leases - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureLeasesScheduleOfFinancialStatementClassificationOfLeaseBalancesWithConsolidatedBalanceSheetDetail" id="Role_DisclosureLeasesScheduleOfFinancialStatementClassificationOfLeaseBalancesWithConsolidatedBalanceSheetDetail">
        <link:definition>100430 - Disclosure - Leases - Schedule of Financial Statement Classification of Lease Balances With Consolidated Balance Sheet (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureLeasesScheduleOfFinancialStatementClassificationOfLeaseBalancesWithConsolidatedBalanceSheetParentheticalDetail" id="Role_DisclosureLeasesScheduleOfFinancialStatementClassificationOfLeaseBalancesWithConsolidatedBalanceSheetParentheticalDetail">
        <link:definition>100440 - Disclosure - Leases - Schedule of Financial Statement Classification of Lease Balances With Consolidated Balance Sheet (Parenthetical) (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureLeasesScheduleOfFinancialStatementClassificationOfLeaseBalancesWithConsolidatedStatementOfOperationsDetail" id="Role_DisclosureLeasesScheduleOfFinancialStatementClassificationOfLeaseBalancesWithConsolidatedStatementOfOperationsDetail">
        <link:definition>100450 - Disclosure - Leases - Schedule of Financial Statement Classification of Lease Balances With Consolidated Statement of Operations (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureLeasesScheduleOfFutureMinimumLeasePaymentsUnderNonCancelableLeasesDetail" id="Role_DisclosureLeasesScheduleOfFutureMinimumLeasePaymentsUnderNonCancelableLeasesDetail">
        <link:definition>100460 - Disclosure - Leases - Schedule of Future Minimum Lease Payments Under Non-cancelable Leases (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureLeasesScheduleOfFutureMinimumLeasePaymentsUnderNonCancelableLeasesDetail2" id="Role_DisclosureLeasesScheduleOfFutureMinimumLeasePaymentsUnderNonCancelableLeasesDetail2">
        <link:definition>100470 - Disclosure - Leases - Schedule of Future Minimum Lease Payments Under Non-cancelable Leases (Detail)2</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureLeasesScheduleOfWeightedAverageRemainingTermAndDiscountRatesDetail" id="Role_DisclosureLeasesScheduleOfWeightedAverageRemainingTermAndDiscountRatesDetail">
        <link:definition>100480 - Disclosure - Leases - Schedule of Weighted Average Remaining Term and Discount Rates (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureLeasesScheduleOfCashFlowsAssociatedWithCompanySLeasingActivitiesDetail" id="Role_DisclosureLeasesScheduleOfCashFlowsAssociatedWithCompanySLeasingActivitiesDetail">
        <link:definition>100490 - Disclosure - Leases - Schedule of Cash Flows Associated With the Company&apos;s Leasing Activities (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureStockBasedCompensationPreTaxAmountsByOperatingSegmentForStockBasedCompensationDetail" id="Role_DisclosureStockBasedCompensationPreTaxAmountsByOperatingSegmentForStockBasedCompensationDetail">
        <link:definition>100500 - Disclosure - Stock-Based Compensation - Pre-tax Amounts by Operating Segment for Stock-Based Compensation (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureStockBasedCompensationAdditionalInformationDetail" id="Role_DisclosureStockBasedCompensationAdditionalInformationDetail">
        <link:definition>100510 - Disclosure - Stock-Based Compensation - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureStockBasedCompensationSummaryOfRestrictedStockUnitsActivityDetail" id="Role_DisclosureStockBasedCompensationSummaryOfRestrictedStockUnitsActivityDetail">
        <link:definition>100520 - Disclosure - Stock-Based Compensation - Summary of Restricted Stock Units Activity (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureStockBasedCompensationSummaryOfRestrictedStockUnitsActivityParentheticalDetail" id="Role_DisclosureStockBasedCompensationSummaryOfRestrictedStockUnitsActivityParentheticalDetail">
        <link:definition>100530 - Disclosure - Stock-Based Compensation - Summary of Restricted Stock Units Activity (Parenthetical) (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetail" id="Role_DisclosureIncomeTaxesAdditionalInformationDetail">
        <link:definition>100540 - Disclosure - Income Taxes - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureShareRepurchaseProgramAdditionalInformationDetail" id="Role_DisclosureShareRepurchaseProgramAdditionalInformationDetail">
        <link:definition>100550 - Disclosure - Share Repurchase Program - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureCommitmentsAndContingenciesAdditionalInformationDetail" id="Role_DisclosureCommitmentsAndContingenciesAdditionalInformationDetail">
        <link:definition>100560 - Disclosure - Commitments and Contingencies - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSegmentInformationAdditionalInformationDetail" id="Role_DisclosureSegmentInformationAdditionalInformationDetail">
        <link:definition>100570 - Disclosure - Segment Information - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSegmentInformationNetSalesByOfferingForNorthAmericaEMEAAndAPACDetail" id="Role_DisclosureSegmentInformationNetSalesByOfferingForNorthAmericaEMEAAndAPACDetail">
        <link:definition>100580 - Disclosure - Segment Information - Net Sales by Offering for North America, EMEA and APAC (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSegmentInformationFinancialInformationAboutReportableOperatingSegmentsDetail" id="Role_DisclosureSegmentInformationFinancialInformationAboutReportableOperatingSegmentsDetail">
        <link:definition>100590 - Disclosure - Segment Information - Financial Information about Reportable Operating Segments (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSegmentInformationSummaryOfTotalAssetsByReportableOperatingSegmentDetail" id="Role_DisclosureSegmentInformationSummaryOfTotalAssetsByReportableOperatingSegmentDetail">
        <link:definition>100600 - Disclosure - Segment Information - Summary of Total Assets by Reportable Operating Segment (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSegmentInformationPreTaxDepreciationAndAmortizationByOperatingSegmentDetail" id="Role_DisclosureSegmentInformationPreTaxDepreciationAndAmortizationByOperatingSegmentDetail">
        <link:definition>100610 - Disclosure - Segment Information - Pre-Tax Depreciation and Amortization by Operating Segment (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureAcquisitionsAdditionalInformationDetail" id="Role_DisclosureAcquisitionsAdditionalInformationDetail">
        <link:definition>100620 - Disclosure - Acquisitions - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureAcquisitionsSummaryOfPurchasePriceAndEstimatedFairValueOfAssetsAcquiredAndLiabilitiesAssumedDetail" id="Role_DisclosureAcquisitionsSummaryOfPurchasePriceAndEstimatedFairValueOfAssetsAcquiredAndLiabilitiesAssumedDetail">
        <link:definition>100630 - Disclosure - Acquisitions - Summary of Purchase Price and Estimated Fair Value of Assets Acquired and Liabilities Assumed (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureAcquisitionsSummaryOfProFormaInformationDetail" id="Role_DisclosureAcquisitionsSummaryOfProFormaInformationDetail">
        <link:definition>100640 - Disclosure - Acquisitions - Summary of Pro Forma Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.insight.com/20200331/taxonomy/role/DisclosureSubsequentEventAdditionalInformationDetail" id="Role_DisclosureSubsequentEventAdditionalInformationDetail">
        <link:definition>100650 - Disclosure - Subsequent Event - Additional Information (Detail)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:element id="nsit_OperatingAndFinanceLeaseLiabilityPaymentsRemainderOfFiscalYear" name="OperatingAndFinanceLeaseLiabilityPaymentsRemainderOfFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_OperatingAndFinanceLeaseLiabilityPaymentsDueYearTwo" name="OperatingAndFinanceLeaseLiabilityPaymentsDueYearTwo" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_OperatingAndFinanceLeaseLiabilityPaymentsDueYearThree" name="OperatingAndFinanceLeaseLiabilityPaymentsDueYearThree" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_OperatingAndFinanceLeaseLiabilityPaymentsDueYearFour" name="OperatingAndFinanceLeaseLiabilityPaymentsDueYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_OperatingAndFinanceLeaseLiabilityPaymentsDueYearFive" name="OperatingAndFinanceLeaseLiabilityPaymentsDueYearFive" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_OperatingAndFinanceLeaseLiabilityPaymentsDueAfterYearFive" name="OperatingAndFinanceLeaseLiabilityPaymentsDueAfterYearFive" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_OperatingAndFinanceLeasesFutureMinimumPaymentsInterestIncludedInPayments" name="OperatingAndFinanceLeasesFutureMinimumPaymentsInterestIncludedInPayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_OperatingAndFinanceLeaseLiability" name="OperatingAndFinanceLeaseLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_OtherAdjustments" name="OtherAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="nsit_AssetBasedLendingFacilityMember" name="AssetBasedLendingFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_RealEstateHeldForSaleTextBlock" name="RealEstateHeldForSaleTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_ContractWithReceivablesAndContractLiabilityTableTextBlock" name="ContractWithReceivablesAndContractLiabilityTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_ScheduleOfLeasesBalancesAndClassifiedOnBalanceSheetTableTextBlock" name="ScheduleOfLeasesBalancesAndClassifiedOnBalanceSheetTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_ScheduleOfMaturitiesOfOperatingAndFinanceLeasesLiabilitiesTableTextBlock" name="ScheduleOfMaturitiesOfOperatingAndFinanceLeasesLiabilitiesTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_ScheduleOfWeightedAverageRemainingTermAndDiscountRatesTableTextBlock" name="ScheduleOfWeightedAverageRemainingTermAndDiscountRatesTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_ScheduleOfOtherInformationRelatedToLeasesTableTextBlock" name="ScheduleOfOtherInformationRelatedToLeasesTableTextBlock" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems" name="OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_OrganizationConsolidationAndPresentationOfFinancialStatementsTable" name="OrganizationConsolidationAndPresentationOfFinancialStatementsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_VNextMember" name="VNextMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_PCMIncMember" name="PCMIncMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_HardwareNetSalesMember" name="HardwareNetSalesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_SoftwareNetSalesMember" name="SoftwareNetSalesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_ServicesNetSalesMember" name="ServicesNetSalesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_NorthAmericaSegmentMember" name="NorthAmericaSegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_EMEASegmentMember" name="EMEASegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_APACSegmentMember" name="APACSegmentMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_LargeEnterpriseCorporateMember" name="LargeEnterpriseCorporateMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_PublicSectorMember" name="PublicSectorMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_SmallAndMediumsizedBusinessesMember" name="SmallAndMediumsizedBusinessesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_AccountsReceivableNetMember" name="AccountsReceivableNetMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_AccruedExpensesAndOtherCurrentLiabilitiesAndOtherLiabilitiesMember" name="AccruedExpensesAndOtherCurrentLiabilitiesAndOtherLiabilitiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_ContractWithCustomerLiabilityCashReceivedInAdvanceAndNotRecognizedAsRevenue" name="ContractWithCustomerLiabilityCashReceivedInAdvanceAndNotRecognizedAsRevenue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_ServicesMember" name="ServicesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_TimeAndMaterialContractsAverageExpectedDuration" name="TimeAndMaterialContractsAverageExpectedDuration" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_IrvineCaliforniaPropertyMember" name="IrvineCaliforniaPropertyMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_ConvertibleSeniorNotesDueTwoThousandTwentyFiveMember" name="ConvertibleSeniorNotesDueTwoThousandTwentyFiveMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_AmountOfFacilityPermittedByQualifiedReceivables" name="AmountOfFacilityPermittedByQualifiedReceivables" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_ForeignCurrencyBorrowingsMember" name="ForeignCurrencyBorrowingsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_ScenarioOneMember" name="ScenarioOneMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_ScenarioTwoMember" name="ScenarioTwoMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_InventoryFinancingFacilityMember" name="InventoryFinancingFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_UnsecuredInventoryFinancingFacilityMember" name="UnsecuredInventoryFinancingFacilityMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_WellsFargoCapitalFinanceLLCMember" name="WellsFargoCapitalFinanceLLCMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_MUFGBankLimitedMember" name="MUFGBankLimitedMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_DebtInstrumentAdditionalPrincipalAmount" name="DebtInstrumentAdditionalPrincipalAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_MeasurementPeriod" name="MeasurementPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_PrincipalAmountPerNoteUsedInConversionRate" name="PrincipalAmountPerNoteUsedInConversionRate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_DebtInstrumentConvertibleSharesPerThousandOfPrincipalAmountOfNotes" name="DebtInstrumentConvertibleSharesPerThousandOfPrincipalAmountOfNotes" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_RepurchasePriceAsPercentageOfPrincipalAmount" name="RepurchasePriceAsPercentageOfPrincipalAmount" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_DebtInstrumentConvertibleRemainingDiscountAccretionPeriod" name="DebtInstrumentConvertibleRemainingDiscountAccretionPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_ConvertibleNoteHedgeTransactionMaturityDate" name="ConvertibleNoteHedgeTransactionMaturityDate" type="xbrli:dateItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_InventoryFinancingFacilityRateIfVendorTermsNotMetEqualPrimePlus" name="InventoryFinancingFacilityRateIfVendorTermsNotMetEqualPrimePlus" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_InventoryFinancingFacilityInterestRateIfBalancesAreNotPaidWithinStatedVendorTerms" name="InventoryFinancingFacilityInterestRateIfBalancesAreNotPaidWithinStatedVendorTerms" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_OptionsToExtendLeaseTermsMember" name="OptionsToExtendLeaseTermsMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_LeaseRightOfUseAsset" name="LeaseRightOfUseAsset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit" />
  <xsd:element id="nsit_LeaseLiability" name="LeaseLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_AccruedExpensesAndOtherCurrentLiabilitiesMember" name="AccruedExpensesAndOtherCurrentLiabilitiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_CurrentPortionOfLongTermDebtMember" name="CurrentPortionOfLongTermDebtMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_FinanceLeaseRightOfUseAssetAccumulatedAmortization" name="FinanceLeaseRightOfUseAssetAccumulatedAmortization" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_OperatingLeaseAbstract" name="OperatingLeaseAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_OperatingAndFinanceLeaseLiabilityPaymentsDue" name="OperatingAndFinanceLeaseLiabilityPaymentsDue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_FinanceLeaseAbstract" name="FinanceLeaseAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_OperatingAndFinanceLeaseLiabilitiesPaymentsDueAbstract" name="OperatingAndFinanceLeaseLiabilitiesPaymentsDueAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedFairValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" />
  <xsd:element id="nsit_PercentageOfAwardVestedUponCompletionOfAcquisition" name="PercentageOfAwardVestedUponCompletionOfAcquisition" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_PerformanceBasedRestrictedStockUnitMember" name="PerformanceBasedRestrictedStockUnitMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_CoronavirusAidReliefAndEconomicSecurityActProvideReliefOfProvisionRelatingToNetOperatingLossCarrybacksRecordInDiscreteTaxBenefit" name="CoronavirusAidReliefAndEconomicSecurityActProvideReliefOfProvisionRelatingToNetOperatingLossCarrybacksRecordInDiscreteTaxBenefit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit" />
  <xsd:element id="nsit_IncomeTaxLineItems" name="IncomeTaxLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_IncomeTaxTable" name="IncomeTaxTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_CoronavirusMember" name="CoronavirusMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="nsit_NumberOfMonthsOfSalaryPaidAsSeveranceOnChangeOfControl" name="NumberOfMonthsOfSalaryPaidAsSeveranceOnChangeOfControl" type="us-types:durationStringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_NumberOfOfficeLocations" name="NumberOfOfficeLocations" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_NumberOfTeammates" name="NumberOfTeammates" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" />
  <xsd:element id="nsit_TempeArizonaAndElSegundoAndSantaMonicaCaliforniaPropertiesMember" name="TempeArizonaAndElSegundoAndSantaMonicaCaliforniaPropertiesMember" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
</xsd:schema>
