<SEC-DOCUMENT>0001094792-17-000006.txt : 20170620
<SEC-HEADER>0001094792-17-000006.hdr.sgml : 20170620
<ACCEPTANCE-DATETIME>20170620165402
ACCESSION NUMBER:		0001094792-17-000006
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170616
FILED AS OF DATE:		20170620
DATE AS OF CHANGE:		20170620

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Upland Software, Inc.
		CENTRAL INDEX KEY:			0001505155
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		IRS NUMBER:				272992077
		STATE OF INCORPORATION:			TX
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		401 CONGRESS AVE.
		STREET 2:		SUITE 1850
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78701
		BUSINESS PHONE:		512-960-1010

	MAIL ADDRESS:	
		STREET 1:		401 CONGRESS AVE.
		STREET 2:		SUITE 1850
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78701

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Silverback Acquisition Corp
		DATE OF NAME CHANGE:	20101105

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MCDONALD JOHN T
		CENTRAL INDEX KEY:			0001094792

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36720
		FILM NUMBER:		17921368

	MAIL ADDRESS:	
		STREET 1:		C/O UPLAND SOFTWARE INC.
		STREET 2:		401 CONGRESS AVE., SUITE 1850
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78701
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_149799202581907.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-06-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001505155</issuerCik>
        <issuerName>Upland Software, Inc.</issuerName>
        <issuerTradingSymbol>UPLD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001094792</rptOwnerCik>
            <rptOwnerName>MCDONALD JOHN T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>401 CONGRESS AVE., STE 1850</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>AUSTIN</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>78701</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-06-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4946</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>21.55</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1966161</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Shares withheld by the issuer to satisfy tax withholding obligations in connection with the vesting of restricted stock awarded under the issuers 2014 Equity Incentive Plan. This is not an open market sale of securities.</footnote>
        <footnote id="F2">Excludes 243,738 shares held indirectly by MLFPF&amp;S as Cust. FBO J.McDonald IRA for a total of 2,209,899 shares.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ John T. McDonald</signatureName>
        <signatureDate>2017-06-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
