<SEC-DOCUMENT>0001289889-17-000007.txt : 20170823
<SEC-HEADER>0001289889-17-000007.hdr.sgml : 20170823
<ACCEPTANCE-DATETIME>20170823163401
ACCESSION NUMBER:		0001289889-17-000007
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170822
FILED AS OF DATE:		20170823
DATE AS OF CHANGE:		20170823

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Hill Michael Douglass
		CENTRAL INDEX KEY:			0001289889

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36720
		FILM NUMBER:		171047436

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

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
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_150352042533472.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-08-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001289889</rptOwnerCik>
            <rptOwnerName>Hill Michael Douglass</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>401 CONGRESS AVE., SUITE 1850</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>AUSTIN</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>78701</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CFO,Treasurer &amp; Secretary</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-08-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>16000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.30</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>328837</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Incentive Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.3</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2017-08-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>16000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2021-03-16</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>16000.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>21383</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">25% of the shares subject to the Option vested on 3/16/2012, and the remaining shares subject to the Option vest in equal 36 installments on the 16th day of each month, in each case subject to the reporting person's continued employment through such vesting dates.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Michael D. Hill</signatureName>
        <signatureDate>2017-08-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
