Initial Registration Statement for Employee Benefit Plan (Form S-8)

As filed with the Securities and Exchange Commission on March 2, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER THE SECURITIES ACT OF 1933

Dyne Therapeutics, Inc.

(Exact Name of Registrant as Specified in Its Charter)

2020 Stock Incentive Plan

(Full Title of the Plan)

John G. Cox

President and Chief Executive Officer

1560 Trapelo Road

Waltham, Massachusetts 02451

(Name and Address of Agent for Service)

(781) 786-8230

(Telephone Number, Including Area Code, of Agent for Service)

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

EXPLANATORY NOTE

This Registration Statement on Form S-8, relating to the 2020 Stock Incentive Plan (the "2020 Plan") of Dyne Therapeutics, Inc. (the "Registrant"), is being filed for the purpose of registering additional securities of the same class as other securities for which a Registration Statement on Form S-8 relating to the 2020 Plan has previously been filed and is effective. Pursuant to General Instruction E to Form S-8, except as otherwise set forth below, this Registration Statement incorporates by reference (i) the contents of the Registration Statement on Form S-8, File No. 333-248873, relating to the 2020 Plan filed by the Registrant with the Securities and Exchange Commission on September 17, 2020, (ii) the contents of the Registration Statement on Form S-8, File No. 333-253863, relating to the 2020 Plan filed by the Registrant with the Securities and Exchange Commission on March 4, 2021, (iii) the contents of the Registration Statement on Form S-8, File No. 333-263409, relating to the 2020 Plan filed by the Registrant with the Securities and Exchange Commission on March 10, 2022, (iv) the contents of the Registration Statement on Form S-8, File No. 333-270206, relating to the 2020 Plan filed by the Registrant with the Securities and Exchange Commission on March 2, 2023, (v) the contents of the Registration Statement on Form S-8, File No. 333-277654, relating to the 2020 Plan filed by the Registrant with the Securities and Exchange Commission on March 5, 2024 and (vi) the contents of the Registration Statement on Form S-8, File No. 333-285305, relating to the 2020 Plan filed by the Registrant with the Securities and Exchange commission on February 27, 2025.

Item 8. Exhibits.

The following exhibits are incorporated herein by reference:

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Waltham, Commonwealth of Massachusetts on this 2nd day of March, 2026.

POWER OF ATTORNEY AND SIGNATURES

We, the undersigned officers and directors of Dyne Therapeutics, Inc., hereby severally constitute and appoint John G. Cox and Erick Lucera, and each of them singly (with full power to each of them to act alone), our true and lawful attorneys with full power of substitution and resubstitution in each of them for him or her and in his or her name, place and stead, and in any and all capacities, to sign for us and in our names in the capacities indicated below, the registration statement on Form S-8 filed herewith and any and all subsequent amendments to said registration statement, and generally to do all such things in our names and on our behalf in our capacities as officers and directors to enable Dyne Therapeutics, Inc. to comply with the provisions of the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission, hereby ratifying and confirming our signatures as they may be signed by our said attorneys, or any of them, to said registration statement and any and all amendments thereto.

Pursuant to the requirements of the Securities Act of 1933, this registration statement has been signed by the following persons in the capacities and on the dates indicated.