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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2021-10-21</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001871509</issuerCik>
        <issuerName>Portillo's Inc.</issuerName>
        <issuerTradingSymbol>PTLO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001761825</rptOwnerCik>
            <rptOwnerName>Bordelon Ann G.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O PORTILLO'S INC.</rptOwnerStreet1>
            <rptOwnerStreet2>2001 SPRING ROAD, SUITE 400</rptOwnerStreet2>
            <rptOwnerCity>OAK BROOK</rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode>60523</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A common stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6000</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>LLC Units of PHD Group Holdings LLC</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>17789</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.37</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2030-05-12</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>59644</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents restricted stock units subject to time-based vesting granted on October 21, 2021, one-third of which vest on each of the first three anniversaries of the grant date, subject to the Reporting Person's continued service with the Issuer and the terms of the applicable award agreement.</footnote>
        <footnote id="F2">Pursuant to the Second Amended and Restated Limited Liability Company Agreement of PHD Group Holdings LLC, dated as of October 20, 2021, LLC Units (as defined therein) held by the Reporting Persons are exchangeable for shares of Class A common stock on a one-for-one basis, subject to certain exceptions, conditions and adjustments. The LLC Units have no expiration date. At the time of any such exchange, an equal number of shares of Class B common stock of the Issuer held by the Reporting Person, which have no economic value and entitle holders thereof to one vote per share on all matters on which stockholders of the Issuer are entitled to vote generally, are cancelled.</footnote>
        <footnote id="F3">Represents options previously granted on 5/12/2020 pursuant to the Issuer's 2014 Equity Incentive Plan, as amended, which were substituted for options to purchase shares of Class A common stock under the Issuer's 2021 Equity Incentive Plan. The options vest in equal annual installments on each of the first five anniversaries of the grant date.</footnote>
    </footnotes>

    <remarks>Exhibit 24 - Power of Attorney (incorporated herein by reference).</remarks>

    <ownerSignature>
        <signatureName>By: /s/ Susan Shelton, as attorney-in-fact for Ann G. Bordelon</signatureName>
        <signatureDate>2021-10-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
