<SEC-DOCUMENT>0000034563-18-000061.txt : 20181114
<SEC-HEADER>0000034563-18-000061.hdr.sgml : 20181114
<ACCEPTANCE-DATETIME>20181114185815
ACCESSION NUMBER:		0000034563-18-000061
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20181112
FILED AS OF DATE:		20181114
DATE AS OF CHANGE:		20181114

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SIERS SCOTT A
		CENTRAL INDEX KEY:			0001699367

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-34249
		FILM NUMBER:		181185581

	MAIL ADDRESS:	
		STREET 1:		FARMER BROS. CO.
		STREET 2:		P O BOX 77057
		CITY:			FORT WORTH
		STATE:			TX
		ZIP:			76177

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FARMER BROTHERS CO
		CENTRAL INDEX KEY:			0000034563
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS FOOD PREPARATIONS & KINDRED PRODUCTS [2090]
		IRS NUMBER:				950725980
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		1912 FARMER BROTHERS DRIVE
		CITY:			NORTHLAKE
		STATE:			TX
		ZIP:			76262
		BUSINESS PHONE:		888 998 2468

	MAIL ADDRESS:	
		STREET 1:		P O BOX 77057
		CITY:			FORT WORTH
		STATE:			TX
		ZIP:			76177
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_154223987951214.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-11-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000034563</issuerCik>
        <issuerName>FARMER BROTHERS CO</issuerName>
        <issuerTradingSymbol>FARM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001699367</rptOwnerCik>
            <rptOwnerName>SIERS SCOTT A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>FARMER BROS. CO.</rptOwnerStreet1>
            <rptOwnerStreet2>1912 FARMER BROTHERS DRIVE</rptOwnerStreet2>
            <rptOwnerCity>NORTHLAKE</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>76262</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SENIOR VP &amp; GM - SALES</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>25.04</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-11-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>9608</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2025-11-12</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9608.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9608</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Performance-Based Restricted Stock Units (PBRSUs)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2018-11-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2985</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2985.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2985</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Grant of non-qualified stock option under the Farmer Bros. Co. 2017 Long-Term Incentive Plan (the &quot;Plan&quot;); the stock option vests pursuant to a three year vesting schedule, whereby one-third of the total number of shares issuable under the option becomes exercisable each year on the anniversary of the grant date, subject to certain continued employment conditions and subject to accelerated vesting in certain circumstances.</footnote>
        <footnote id="F2">Represents only the stock options granted on the Transaction Date and does not include stock options with different prices and/or vesting terms.</footnote>
        <footnote id="F3">Grant of performance-based restricted stock units (&quot;PBRSUs&quot;) under the Plan. The target number of PBRSUs is presented in the table. Subject to certain continued employment conditions and subject to accelerated vesting in certain circumstances, the PBRSUs are scheduled to vest based on achievement of certain financial performance goals for the performance period July 1, 2018 through June 30, 2021. At the end of the three-year performance period, the number of PBRSUs that actually vest will be 0% to 150% of the target amount set forth in Table II, Item 5, depending on the extent to which Farmer Bros. Co. meets or exceeds certain financial performance goals measured over the full three-year performance period.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Thomas J. Mattei, Jr., Attorney-In-Fact for Scott A. Siers</signatureName>
        <signatureDate>2018-11-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
