<?xml version="1.0" encoding="us-ascii"?>
<!-- DFIN - Donnelley Financial Solutions, Inc. -->
<!-- CTU Version: 75.1.2 -->
<!-- Creation date: 5/19/2026 10:55:12 PM Eastern Time -->
<!-- Copyright (c) 2026 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
<xsd:schema
  xmlns:t="http://att.com/20260514"
  xmlns:xbrli="http://www.xbrl.org/2003/instance"
  xmlns:link="http://www.xbrl.org/2003/linkbase"
  xmlns:xlink="http://www.w3.org/1999/xlink"
  xmlns:xbrldt="http://xbrl.org/2005/xbrldt"
  xmlns:dtr-types="http://www.xbrl.org/dtr/type/2022-03-31"
  xmlns:us-gaap="http://fasb.org/us-gaap/2025"
  xmlns:dei="http://xbrl.sec.gov/dei/2025"
  xmlns:us-types="http://fasb.org/us-types/2025"
  attributeFormDefault="unqualified"
  elementFormDefault="qualified"
  targetNamespace="http://att.com/20260514"
  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://www.xbrl.org/dtr/type/2022-03-31/types.xsd" namespace="http://www.xbrl.org/dtr/type/2022-03-31" />
    <xsd:import schemaLocation="https://xbrl.sec.gov/dei/2025/dei-2025.xsd" namespace="http://xbrl.sec.gov/dei/2025" />
    <xsd:import schemaLocation="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd" namespace="http://fasb.org/us-gaap/2025" />
    <xsd:import schemaLocation="https://xbrl.fasb.org/us-gaap/2025/elts/us-types-2025.xsd" namespace="http://fasb.org/us-types/2025" />
  <xsd:annotation>
    <xsd:appinfo>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="t-20260514_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="t-20260514_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:title="Presentation Links, all" xlink:type="simple" />
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="t-20260514_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:title="Definition Links, all" xlink:type="simple" />
      <link:roleType roleURI="http://att.com//20260514/taxonomy/role/DocumentDocumentAndEntityInformation" id="DocumentDocumentAndEntityInformation">
        <link:definition>000001 - 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>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:element id="t_ATTInc0250GlobalNotesDueMarch42026Member" name="ATTInc0250GlobalNotesDueMarch42026Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc1800GlobalNotesDueSeptember52026Member" name="ATTInc1800GlobalNotesDueSeptember52026Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc2900GlobalNotesDueDecember42026Member" name="ATTInc2900GlobalNotesDueDecember42026Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTIncFloatingRateGlobalNotesDueSeptember162027Member" name="ATTIncFloatingRateGlobalNotesDueSeptember162027Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc1600GlobalNotesDueMay192028Member" name="ATTInc1600GlobalNotesDueMay192028Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc2350GlobalNotesDueSeptember52029Member" name="ATTInc2350GlobalNotesDueSeptember52029Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc4375GlobalNotesDueSeptember142029Member" name="ATTInc4375GlobalNotesDueSeptember142029Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc2600GlobalNotesDueDecember172029Member" name="ATTInc2600GlobalNotesDueDecember172029Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc0800GlobalNotesDueMarch42030Member" name="ATTInc0800GlobalNotesDueMarch42030Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc.3.150GlobalNotesDueJune12030Member" name="ATTInc.3.150GlobalNotesDueJune12030Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc3950GlobalNotesDueApril302031Member" name="ATTInc3950GlobalNotesDueApril302031Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc2050GlobalNotesDueMay192032Member" name="ATTInc2050GlobalNotesDueMay192032Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc3550GlobalNotesDueDecember172032Member" name="ATTInc3550GlobalNotesDueDecember172032Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc3.600GlobalNotesDueJune12033Member" name="ATTInc3.600GlobalNotesDueJune12033Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc5200GlobalNotesDueNovember182033Member" name="ATTInc5200GlobalNotesDueNovember182033Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc3375GlobalNotesDueMarch152034Member" name="ATTInc3375GlobalNotesDueMarch152034Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc4300GlobalNotesDueNovember182034Member" name="ATTInc4300GlobalNotesDueNovember182034Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc2450GlobalNotesDueMarch152035Member" name="ATTInc2450GlobalNotesDueMarch152035Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc3150GlobalNotesDueSeptember42036Member" name="ATTInc3150GlobalNotesDueSeptember42036Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc4.050GlobalNotesDueJune12037Member" name="ATTInc4.050GlobalNotesDueJune12037Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc2600GlobalNotesDueMay192038Member" name="ATTInc2600GlobalNotesDueMay192038Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc1800GlobalNotesDueSeptember142039Member" name="ATTInc1800GlobalNotesDueSeptember142039Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc7000GlobalNotesDueApril302040Member" name="ATTInc7000GlobalNotesDueApril302040Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc4250GlobalNotesDueJune12043Member" name="ATTInc4250GlobalNotesDueJune12043Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc4875GlobalNotesDueJune12044Member" name="ATTInc4875GlobalNotesDueJune12044Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc4000GlobalNotesDueJune12049Member" name="ATTInc4000GlobalNotesDueJune12049Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc4250GlobalNotesDueMarch12050Member" name="ATTInc4250GlobalNotesDueMarch12050Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc3750GlobalNotesDueSeptember12050Member" name="ATTInc3750GlobalNotesDueSeptember12050Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
  <xsd:element id="t_ATTInc5350GlobalNotesDueNovember12066Member" name="ATTInc5350GlobalNotesDueNovember12066Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true" />
</xsd:schema>
