Foghorn Therapeutics Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No. )

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

FOGHORN THERAPEUTICS INC.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

NOTICE OF 2025 ANNUAL MEETING OF STOCKHOLDERS

The 2025 Annual Meeting of Stockholders (the “Annual Meeting”) of Foghorn Therapeutics Inc. (the “Company” or “Foghorn”) will be held on June 17, 2025, at 9 a.m. Eastern Time. The Annual Meeting will be a virtual-only meeting. In order to attend the Annual Meeting, you must register atwww.proxydocs.com/FHTX. Upon completing your registration, you will receive further instructions via email, including a unique link that will allow you to access, and to vote and submit questions during, the Annual Meeting. Details regarding how to attend and vote at the Annual Meeting are more fully described in the Important Notice Regarding the Availability of Proxy Materials, your proxy card and our proxy statement.

The Annual Meeting will be held for the purpose of considering and voting on the following Company-sponsored proposals:

We will also consider and act upon any other matters that properly come before the Annual Meeting or any adjournment or postponement thereof.

These proposals are more fully described in the proxy statement accompanying this notice. This notice, our proxy statement and our Annual Report on Form 10-K for the year ended December 31, 2024 can be accessed at the following website: www.proxydocs.com/FHTX.

Our Board of Directors recommends that you vote “for” each nominee for Class II director (Proposal No. 1) and “for” ratification of the proposed independent registered public accounting firm (Proposal No. 2).

April 28, 2025 has been fixed as the record date for the determination of the stockholders entitled to notice of and to vote at the Annual Meeting or any adjournments thereof.

Your vote is important. Whether or not you expect to attend the virtual-only Annual Meeting, we urge you to vote your shares by following the instructions in the Important Notice Regarding the Availability of Proxy Materials that you previously received and submit your proxy by the Internet or telephone or by signing, dating and returning your proxy card in order to ensure that your vote is recorded. If you choose to attend the virtual-only Annual Meeting, you may still vote your shares during the Annual Meeting, even if you have previously voted or returned your proxy by any of the methods described in our proxy statement. If your shares are held in a bank or brokerage account, please refer to the materials provided by your bank or broker for voting instructions.

All stockholders are extended a cordial invitation to attend the virtual-only Annual Meeting. Thank you for your ongoing support of and interest in Foghorn Therapeutics Inc.

By Order of the Board of Directors

Adrian Gottschalk

Chief Executive Officer

May 5, 2025

TABLE OF CONTENTS

i

PROXY STATEMENT FOR 2025 ANNUAL MEETING OF STOCKHOLDERS

To Be Held on Tuesday, June 17, 2025 at 9 a.m. Eastern Time

This proxy statement, along with the accompanying Notice of 2025 Annual Meeting of Stockholders, contains information about the 2025 Annual Meeting of Stockholders of Foghorn Therapeutics Inc., including any adjournments or postponements of the meeting, which we refer to as the “Annual Meeting.” The Annual Meeting will be conducted virtually only, via live webcast, at 9 a.m. Eastern Time on June 17, 2025.

In this proxy statement, we refer to Foghorn Therapeutics Inc. as “Foghorn,” “the Company,” “we” and “us.”

This proxy statement relates to the solicitation of proxies by our Board of Directors for use at the Annual Meeting.

On or about May 5, 2025, we made available this proxy statement and the attached Notice of 2025 Annual Meeting of Stockholders to all stockholders entitled to vote at the Annual Meeting, and we began sending the Important Notice Regarding the Availability of Proxy Materials to those stockholders. Although not part of this proxy statement, we have also made available with this proxy statement our Annual Report on Form 10-K for the year ended December 31, 2024, containing our financial statements for the fiscal year ended December 31, 2024.