As filed with the Securities and Exchange Commission on August 12, 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

ACRIVON THERAPEUTICS, INC.

(Exact name of Registrant as specified in its charter)

480 Arsenal Way, Suite 100

Watertown, Massachusetts 02472

(Address of principal executive offices) (Zip code)

Acrivon Therapeutics, Inc. Amended and Restated 2022 Equity Incentive Plan

(Full title of the plan)

Peter Blume-Jensen, M.D., Ph.D.

Chief Executive Officer and President

Acrivon Therapeutics, Inc.

480 Arsenal Way, Suite 100

Watertown, Massachusetts 02472

(Name and address of agent for service)

(617) 207-8979

(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

Acrivon Therapeutics, Inc. (the “Registrant”) is filing this Registration Statement on Form S-8 for the purpose of registering 3,000,000 shares of the Registrant’s Common Stock, par value $0.001 per share (the “Common Stock”), issuable to eligible persons under the Acrivon Therapeutics, Inc. Amended and Restated 2022 Equity Incentive Plan (the “A&R 2022 Plan”), which Common Stock is in addition to the shares of Common Stock registered on the Registrant’s Form S-8 filed with the Securities and Exchange Commission (the “Commission”) on November  17, 2022 (File No. 333-268426), March  29, 2023 (File No. 333-270923), March  29, 2024 (File No. 333-278365), March  28, 2025 (File No. 333-286208), and March  19, 2026 (File No. 333-294425) (collectively, the “Prior Registration Statements”).

This Registration Statement relates to securities of the same class as that to which the Prior Registration Statements relate and is submitted in accordance with General Instruction E to Form S-8 regarding Registration of Additional Securities. Pursuant to General Instruction E of Form S-8, the contents of the Prior Registration Statements, to the extent relating to the registration of Common Stock issuable under the A&R 2022 Plan, are incorporated herein by reference and made part of this Registration Statement, except as amended hereby.

PART I

INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

The information specified in Item 1 and Item 2 of Part I of Form S-8 is omitted from this Registration Statement. The documents containing the information specified in Part I of Form S-8 will be delivered to the participants in the A&R 2022 Plan as specified by Rule 428(b)(1) under the Securities Act of 1933, as amended (the “Securities Act”).

PART II

The following documents filed by the Registrant with the Commission are incorporated by reference into this Registration Statement:

All documents subsequently filed by the Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits furnished on such form that relate to such items, prior to the filing of a post-effective amendment to this Registration Statement which indicates that all of the shares of Common Stock offered have been sold or which deregisters all of such shares then remaining unsold, shall be deemed to be incorporated by reference in this Registration Statement and to be a part hereof from the date of the filing of such documents.

For purposes of this Registration Statement, any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

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 Watertown, Commonwealth of Massachusetts, on this 12th day of August, 2026.

POWER OF ATTORNEY

KNOW ALL BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Peter Blume-Jensen and Adam Levy, and each of them, as his or her true and lawful agents, proxies and attorneys-in-fact, with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to (i) act on, sign and file with the Securities and Exchange Commission any and all amendments (including post-effective amendments) to this Registration Statement together with all schedules and exhibits thereto and any subsequent registration statement filed pursuant to Rule 462(b) under the Securities Act, together with all schedules and exhibits thereto, (ii) act on, sign and file such certificates, instruments, agreements and other documents as may be necessary or appropriate in connection therewith, (iii) act on and file any supplement to any prospectus included in this Registration Statement or any such amendment or any subsequent registration statement filed pursuant to Rule 462(b) under the Securities Act, and (iv) take any and all actions which may be necessary or appropriate to be done, as fully for all intents and purposes as he might or could do in person, hereby approving, ratifying and confirming all that such agent, proxy and attorney-in-fact or any of his substitutes may lawfully do or cause to be done by virtue thereof.

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

Exhibit 5.1

August 12, 2026

Acrivon Therapeutics, Inc.

480 Arsenal Way, Suite 100

Watertown, Massachusetts 02472

Ladies and Gentlemen:

We refer to the Registration Statement on Form S-8 (the “Registration Statement”) being filed by Acrivon Therapeutics, Inc., a Delaware corporation (the “Company”), with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the “Securities Act”), relating to the registration of 3,000,000 shares of Common Stock which may be issued under the Acrivon Therapeutics, Inc. Amended and Restated 2022 Equity Incentive Plan (the “A&R 2022 Plan,” and the aggregate shares of Common Stock to be registered under the Registration Statement, the “Registered Shares”).

This opinion letter is being delivered in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act.

We have examined the Registration Statement, the Company’s Second Amended and Restated Certificate of Incorporation, the Company’s Amended and Restated Bylaws, the A&R 2022 Plan, the resolutions adopted by the board of directors of the Company relating to the Registration Statement and the A&R 2022 Plan, and the proposal adopted by the stockholders of the Company at the Company’s 2026 Annual Meeting of Stockholders relating to the A&R 2022 Plan. We have also examined originals, or copies of originals certified to our satisfaction, of such agreements, documents, certificates and statements of the Company and other corporate documents and instruments, and have examined such questions of law, as we have considered relevant and necessary as a basis for this opinion letter. We have assumed the authenticity of all documents submitted to us as originals, the genuineness of all signatures, the legal capacity of all persons and the conformity with the original documents of any copies thereof submitted to us for examination. As to facts relevant to the opinions expressed herein, we have relied without independent investigation or verification upon, and assumed the accuracy and completeness of, certificates, letters and oral and written statements and representations of public officials and officers and other representatives of the Company.

Sidley Austin LLP is a limited liability partnership practicing in affiliation with other Sidley Austin partnerships.

Acrivon Therapeutics, Inc.

August 12, 2026

Page 2

Based on the foregoing, we are of the opinion that each Registered Share that is newly issued pursuant to the A&R 2022 Plan will be validly issued, fully paid and non-assessable when: (i) the Registration Statement, as finally amended, shall have become effective under the Securities Act; (ii) such Registered Share shall have been duly issued and delivered in accordance with the A&R 2022 Plan; and (iii) a certificate representing such Registered Share shall have been duly executed, countersigned and registered and duly delivered to the person entitled thereto against payment of the agreed consideration therefor (in an amount not less than the par value thereof) or, if any such Registered Share is to be issued in uncertificated form, the Company’s books shall reflect the issuance of such Registered Share to the person entitled thereto against payment of the agreed consideration therefor (in an amount not less than the par value thereof), all in accordance with the A&R 2022 Plan.

This opinion letter is limited to the General Corporation Law of the State of Delaware. We express no opinion as to the laws, rules or regulations of any other jurisdiction, including, without limitation, the federal laws of the United States of America or any state securities or blue sky laws.

We hereby consent to the filing of this opinion letter as an exhibit to the Registration Statement and to all references to our Firm included in or made a part of the Registration Statement. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act.

Exhibit 23.2

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of Acrivon Therapeutics, Inc. of our report dated March 19, 2026 relating to the financial statements, which appears in Acrivon Therapeutics, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2025.

1