UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-A

FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES

PURSUANT TO SECTION 12(b) OR (g) OF

THE SECURITIES EXCHANGE ACT OF 1934

Avalyn Pharma Inc.

(Exact name of registrant as specified in its charter)

Securities to be registered pursuant to Section 12(b) of the Act:

If this form relates to the registration of a class of securities pursuant to Section 12(b) of the Exchange Act and is effective pursuant to General Instruction A.(c) or (e), check the following box. ☒

If this form relates to the registration of a class of securities pursuant to Section 12(g) of the Exchange Act and is effective pursuant to General Instruction A.(d) or (e), check the following box. ☐

If this form relates to the registration of a class of securities concurrently with a Regulation A offering, check the following box. ☐

Securities Act registration statement file or Regulation A offering statement number to which this form relates (if applicable):

333-294932

Securities to be registered pursuant to Section 12(g) of the Act:

None

Item 1. Description of Registrant’s Securities to be Registered.

For a description of Avalyn Pharma Inc.’s (the “Registrant”) common stock, par value $0.001 per share (the “Common Stock”), to be registered hereunder, reference is made to the information set forth under the heading “Description of Capital Stock” in the Registrant’s prospectus that constitutes a part of the Registrant’s Registration Statement on Form S-1 (File No. 333-294932) initially filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), on April 8, 2026, including exhibits, and as amended from time to time (the “Registration Statement”), which information is hereby incorporated by reference. The description of the Common Stock included in any form of prospectus subsequently filed by the Registrant with the Commission pursuant to Rule 424(b) under the Securities Act that constitutes part of the Registration Statement shall be deemed to be incorporated by reference herein.

Item 2. Exhibits.

In accordance with the “Instructions as to Exhibits” with respect to Form 8-A, no exhibits are required to be filed as part of this registration statement because no other securities of the Registrant are registered on The Nasdaq Stock Market LLC and the securities registered hereby are not being registered pursuant to Section 12(g) of the Securities Exchange Act of 1934, as amended.

SIGNATURE

Pursuant to the requirements of Section 12 of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereto duly authorized.