Dorman Products Inc

Record Date

The Board has fixed the close of business on March 26, 2025 as the “record date” for the determination of shareholders entitled to receive notice of, and to vote at, the annual meeting and any

postponements or adjournments of the annual meeting. As of the close of business on the record date, there were 30,558,021 shares of our common stock, par value $0.01 per share, outstanding.

Voting Matters and Votes Per Share

At the annual meeting, shareholders will consider and vote upon:

The Board is not aware of any other matters that will come before the annual meeting or any postponements or adjournments thereof. Shareholders have one vote per share on all matters to be presented at the annual meeting.

How to Vote

Voting by Shareholders of Record

If you are a shareholder of record, you may vote online while attending the annual meeting. If you do not wish to vote at that time, or if you will not be attending the annual meeting, you may vote by proxy. You may vote over the Internet, before and during the annual meeting, or by mail or telephone by following the instructions provided in your proxy card. Voting online during the annual meeting will replace any previous votes you may have cast.

Voting by Beneficial Owners

If your shares are held in an account at a brokerage firm, bank, broker-dealer, or other similar organization, then you are the beneficial owner of shares held in “street name.” If you hold your shares in “street name,” please check the materials provided to you by your broker, bank, or other nominee to determine how you may vote your shares. As a beneficial owner, you have the right to direct the broker, bank, or other nominee holding your shares on how to vote the shares held in your account using the voting instructions received from such organization. The availability of Internet or telephone voting will depend on the voting process of your broker, bank, or other nominee. Shares held in “street name” may be voted online during the annual meeting only if you obtain a legal proxy from the broker, bank, or other nominee giving you the right to vote the shares.

Voting by participants in the Dorman Products, Inc. 401(k) Retirement Plan and Trust

If you are a participant in the Dorman Products, Inc. 401(k) Retirement Plan and Trust, referred to as the “401(k) Retirement Plan,” and shares of common stock of the Company are credited to your plan account, you have the right to direct Vanguard Fiduciary Trust Company, trustee of the 401(k) Retirement Plan, on how to vote such shares. To provide instructions to the trustee on how to vote your plan shares, simply vote your plan shares by following the instructions provided in your proxy card, which permits voting electronically via the Internet, by telephone, or in writing. The trustee of the 401(k) Retirement Plan will have the votes of each participant tabulated by Broadridge and will vote the 401(k) Retirement Plan’s shares on a basis proportionally consistent with the tabulated votes of such participants by submitting a final proxy card representing the plan shares for inclusion in the tally at the annual meeting. If you do not vote the plan shares credited to your account, the trustee will not have direction as to how to vote such shares and you will be treated as directing the trustee to vote your plan shares in the same proportion as the shares for which the trustee has received timely instruction from others who do vote. To allow sufficient time for the trustee to vote your plan shares, your vote must be received by 11:59 p.m., EDT, on May 13, 2025.

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Voting by Proxy

A proxy is your legal designation of another person, also referred to as the “proxy,” to vote on your behalf. By properly signing and returning the proxy card or by voting by Internet or telephone, you are giving the persons who our Board designated as proxies the authority to vote your shares in the manner that you indicate on your proxy card or by voting by Internet or telephone.

If you vote electronically via the Internet or by telephone, you will need your control number (your control number can be found on your proxy card).

If you vote electronically via the Internet or by telephone, you do not need to return your proxy card.

Please note that although the Company and its agents will not charge you for voting via the Internet or by telephone, you may incur other third-party costs, such as usage charges of your Internet and telephone service providers. We do not cover these costs; they are solely your responsibility.

Whether or not you plan to attend the annual meeting, we urge you to vote promptly using one of these methods to ensure your vote is counted.

How to Revoke Your Proxy

Proxies may be revoked prior to being voted at the annual meeting. You may revoke a proxy before its exercise by filing written notice of revocation with Broadridge before the annual meeting (notice of revocation must be received by the day before the annual meeting). After voting, you may change your vote one or more times by completing and returning a later-dated proxy to Broadridge, by voting again by Internet or telephone as described in this proxy statement, or by voting when prompted during the annual meeting live webcast. Attendance at the annual meeting will not in itself constitute a revocation of your proxy. You may request a new proxy card from Broadridge. The last vote received chronologically will supersede any prior votes. The deadline for registered shareholders to change their vote via proxy is 11:59 p.m. EDT on May 15, 2025 (mailed proxy cards must be received by the day before the annual meeting). All requests and correspondence with

Broadridge should be mailed to Voting Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, New York 11717. If you are a beneficial owner of shares of common stock held in street name, please review the voting instructions provided by the broker, bank or other nominee holding your shares or contact such organization regarding how to change your vote. If you are a participant in the 401(k) Retirement Plan and shares of common stock of the Company are credited to your plan account, you may revoke a proxy before its exercise by filing written notice of revocation with Broadridge and you may change your vote one or more times by completing and returning a later dated proxy to Broadridge or by voting again by Internet or telephone. The deadline for participants in the 401(k) Retirement Plan to revoke or change their vote is 11:59 p.m. EDT on May 13, 2025 (notices of revocation and mailed proxy cards must be received by May 13, 2025).

Quorum

A quorum of shareholders is necessary to hold a valid annual meeting. Presence at the annual meeting via webcast or by proxy of the holders of a majority of our issued and outstanding common stock as of the close of business on the record date is necessary to constitute a quorum. All shares present via webcast or represented by proxy (including abstentions and broker non-votes) are counted for quorum purposes.

If the annual meeting is adjourned because of the absence of a quorum, those shareholders entitled to vote who attend the adjourned annual meeting,

although constituting less than a quorum as provided herein, shall nevertheless constitute a quorum for the purpose of electing directors. If the annual meeting is adjourned for one or more periods aggregating at least fifteen (15) days because of the absence of a quorum, those shareholders entitled to vote who attend the reconvened annual meeting, if less than a quorum as determined under applicable law, shall nevertheless constitute a quorum for the purpose of acting upon any matter set forth in the Notice of Annual Meeting of Shareholders.

Vote Required and Method of Counting Votes

The table below summarizes the votes required for approval of each matter to be brought before the annual meeting, as well as the treatment of abstentions and broker non-votes.

If you are a registered shareholder and sign and return a proxy but do not specify how you want your shares voted, your shares will be voted FOR each of the director nominees and FOR the other proposals listed above.

If you are a beneficial owner of shares held in street name and do not provide the broker, bank, or other nominee that holds your shares with specific voting instructions, under the rules of various national and regional securities exchanges, the broker, bank, or other nominee that holds your shares may generally vote on “routine” matters but cannot vote on “non-routine” matters. If the broker, bank, or other

nominee that holds your shares does not receive instructions from you on how to vote your shares on a non-routine matter, the organization that holds your shares will not be able to vote your shares on such matter, often referred to as a broker non-vote. The election of directors and the advisory vote on the compensation of our named executive officers are considered non-routine under applicable regulatory rules. The ratification of the appointment of KPMG as our independent registered public accounting firm for the 2025 fiscal year is considered routine under applicable regulatory rules.

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PRINCIPAL ACCOUNTANT FEES AND SERVICES

Aggregate fees for professional services rendered for the Company by KPMG as of and for the fiscal years ended December 31, 2024 and 2023 are set forth in the table below. The Audit Committee has considered and determined that the related services provided by KPMG are compatible with KPMG maintaining its independence.

Audit Fees

Audit fees for the fiscal years ended December 31, 2024 and 2023 were for professional services rendered for the audits of our consolidated financial statements and for the audit of our internal control over financial reporting as required by the Sarbanes-Oxley Act of 2002, quarterly reviews, issuance of consents, and assistance with review of documents filed with the SEC.

Audit-Related Fees

Audit-related fees are for assurance and related services that are reasonably related to the performance of the audit or review of our consolidated financial statements that are not

reported under “Audit Fees.” Audit-related fees for the fiscal year ended December 31, 2024 are for audit-related services associated with a planned system implementation.

Tax Fees

Tax fees for the fiscal years ended December 31, 2024 and 2023 were for professional services relating to trade compliance, tax compliance, tax advice, and tax planning.

All Other Fees

All other fees for the fiscal years ended December 31, 2024 and 2023 were for an annual subscription to KPMG’s accounting research software.