<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-09-04</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001102993</issuerCik>
        <issuerName>LIVEPERSON INC</issuerName>
        <issuerTradingSymbol>LPSN</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001180246</rptOwnerCik>
            <rptOwnerName>ZINGALE ANTHONY</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O LIVEPERSON, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>530 7TH AVE., FLOOR M1</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10018</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2026-09-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>26666</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>26666</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On September 4, 2026, pursuant to the terms of the Amended and Restated Merger Agreement, dated as of July 2, 2026 (the &quot;Merger Agreement&quot;), by and among the Issuer, SoundHound AI, Inc., a Delaware corporation (the &quot;Parent&quot;), Lightspeed Merger Sub Inc., a Delaware corporation and an indirect wholly owned subsidiary of Parent (&quot;Merger Sub&quot;), and Lightspeed Merger Sub II Inc., a Delaware corporation and an indirect wholly owned subsidiary of Parent (&quot;Merger Sub II&quot;), Merger Sub merged with and into the Issuer and immediately thereafter, Merger Sub II merged with and into the Issuer, with the Issuer continuing as the surviving corporation as an indirect wholly owned subsidiary of Parent (the &quot;Mergers&quot;).</footnote>
        <footnote id="F2">Pursuant to the Merger Agreement, each option to acquire shares of Issuer common stock (each &quot;Option&quot;) previously granted by the Issuer to the reporting person that was outstanding and unexercised immediately prior to the First Effective Time (as defined in the Merger Agreement), whether vested or unvested, was cancelled without any payment in respect thereof because the per-share exercise price of each Option exceeded the Per Share Cash Equivalent Consideration (as defined in the Merger Agreement).</footnote>
        <footnote id="F3">This number reflects the Issuer's 1-for-15 reverse stock split effected October 13, 2025.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Monica L. Greenberg, Attorney-in-Fact for Anthony Zingale</signatureName>
        <signatureDate>2026-09-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
