<SEC-DOCUMENT>0001624067-16-000009.txt : 20161219
<SEC-HEADER>0001624067-16-000009.hdr.sgml : 20161219
<ACCEPTANCE-DATETIME>20161219171833
ACCESSION NUMBER:		0001624067-16-000009
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20161216
FILED AS OF DATE:		20161219
DATE AS OF CHANGE:		20161219

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:			Mattox Timothy
		CENTRAL INDEX KEY:			0001624067

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36720
		FILM NUMBER:		162059683

	MAIL ADDRESS:	
		STREET 1:		401 CONGRESS AVE, SUITE 1850
		CITY:			AUSTIN
		STATE:			TX
		ZIP:			78701
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_148218590071661.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-12-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001624067</rptOwnerCik>
            <rptOwnerName>Mattox Timothy</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>President &amp; COO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-12-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>35803</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.75</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>335113</value>
                </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>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Kirk Larson, Attorney-in-Fact</signatureName>
        <signatureDate>2016-12-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
