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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-01-17</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001080014</issuerCik>
        <issuerName>Innoviva, Inc.</issuerName>
        <issuerTradingSymbol>INVA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001485939</rptOwnerCik>
            <rptOwnerName>ABERCROMBIE GEORGE B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2000 SIERRA POINT PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 500</rptOwnerStreet2>
            <rptOwnerCity>BRISBANE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94005</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr. VP &amp; Chief Comm. Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-01-17</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>106718</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>275193</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Includes 53,358 shares of common stock granted pursuant to a time-based restricted stock award (RSA).  Twenty-five percent of the shares subject to the RSA shall vest on February 20, 2018, and 6.25% of the shares subject to the RSA shall vest quarterly thereafter on the Issuer's standard vesting dates until February 20, 2021, provided that the Reporting Person has provided continuous service to the Issuer through the applicable vesting date.</footnote>
        <footnote id="F2">Includes shares of common stock granted pursuant to a performance-based restricted stock award (PSA).  The shares vest pursuant to the PSA over a two-year and three-year performance period upon, and subject to a formula related to, the Issuer's achievement of certain levels of relative total shareholder return (TSR).  The &quot;target&quot; number of shares that may vest is 26,680, but the actual number of shares that may vest will range from 0 to 53,360 shares based on the Issuer's relative TSR over the performance periods.  Subject to achievement of the performance-based vesting conditions, (i) two-thirds of the shares eligible to vest based on achievement for the two-year performance period will vest on February 20, 2019 and the remaining one-third of such shares will vest on February 20, 2020 and (ii) the share eligible to vest based on achievement for the three-year performance period will vest on February 20, 2020, in each case, (continued in Footnote 3)</footnote>
        <footnote id="F3">(continued from Footnote 2) provided that the Reporting Person has provided continuous service to the Issuer through the applicable vesting date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>George Abercrombie</signatureName>
        <signatureDate>2017-01-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
