Q32 Bio 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:

Q32 Bio 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):

Q32 Bio Inc.

NOTICE OF 2025 ANNUAL MEETING OF STOCKHOLDERS

To be held Friday, June 13, 2025

Notice is hereby given that the 2025 Annual Meeting of Stockholders (the “Annual Meeting”) of Q32 Bio Inc. (“we,” “our,” “us,” or the “Company”), will be held on Friday, June 13, 2025 at 9:00 a.m. Eastern Time. The Annual Meeting will be held entirely online. You will be able to attend and participate in the Annual Meeting online by visiting www.virtualshareholdermeeting.com/QTTB2025 and entering the 16-digit control number included on your proxy card. You will not be able to attend the Annual Meeting in person. The purpose of the Annual Meeting is the following:

To elect David Grayzel, M.D., Isaac Manke, Ph.D. and Diyong Xu as Class I directors to our Board of Directors, each to serve until the 2028 Annual Meeting of stockholders and until his successor has been duly elected and qualified, or until his earlier death, resignation, or removal (“Proposal No. 1”);

To approve an amendment to our Restated Certificate of Incorporation, as amended, to limit the liability of certain officers as permitted by amendments to Delaware law (“Proposal No. 2”);

To ratify the appointment of Ernst & Young LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2025 (“Proposal No. 3”);

To approve, on a non-binding, advisory basis, the compensation of our named executive officers (“Proposal No. 4”);

To approve, on a non-binding, advisory basis, the preferred frequency of future advisory votes on compensation of our named executive officers (“Proposal No. 5”);

To approve the adjournment of the Annual Meeting to the extent there are insufficient votes at the Annual Meeting to approve Proposal No. 2 above (“Proposal No. 6”); and

To transact any other business properly brought before the Annual Meeting or any adjournment or postponement of the Annual Meeting.

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Only Q32 Bio Inc. stockholders of record at the close of business on April 16, 2025 will be entitled to vote at the Annual Meeting and any adjournment or postponement thereof. You can find more information, including information regarding the nominees for election to our Board of Directors, in the accompanying proxy statement.

We are pleased to comply with the rules of the Securities and Exchange Commission (the “SEC”) that allow companies to distribute their proxy materials over the Internet under the “notice and access” approach. As a result, we are mailing to our stockholders a Notice of Internet Availability of Proxy Materials (the “Notice of Internet Availability of Proxy Materials”), instead of a paper copy of our proxy materials and our Annual Report for the fiscal year ended December 31, 2024 (the “2024 Annual Report”). We will mail the Notice of Internet Availability of Proxy Materials on or about April 29, 2025 and it contains instructions on how to access those documents and to cast your vote over the Internet. This process allows us to provide our stockholders with the information they need on a more timely basis, while reducing the environmental impact and lowering the costs of printing and distributing our proxy materials. If you would like to receive a printed copy of our proxy materials, including our proxy statement, our 2024 Annual Report and a form of proxy card, free of charge, please follow the instructions on the Notice of Internet Availability of Proxy Materials.

The Board of Directors recommends that you vote “FOR” of each of proposals one, two, three, four, and six and “FOR” the recommendation, on an advisory basis, that the preferred frequency of future votes on the compensation of our named executive officers be on a one year basis; as outlined in the accompanying proxy statement.

Your vote is important. Whether or not you are able to attend the meeting online, it is important that your shares be represented. To ensure that your vote is recorded promptly, please vote as soon as possible, even if you plan to attend the meeting online, by submitting your proxy via the Internet at the address listed on the proxy card or by signing, dating, and returning the proxy card.

By order of the Board of Directors,

/s/ Jodie Morrison

Jodie MorrisonChief Executive Officer

Waltham, Massachusetts

April 29, 2025

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