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 12(g) OF THE

SECURITIES EXCHANGE ACT OF 1934

Mountain Crest Acquisition 6 Corp.

(Exact name of registrant as specified in its charter)

524 Broadway

11th Floor

New York, NY 10012

(Address of principal executive offices, including zip code)

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 number to which this form relates: 333-294891

Securities to be registered pursuant to Section 12(g) of the Act: None.

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

A description of the units, ordinary shares and rights to be registered hereunder is contained in the section entitled “Description of Securities” in the Prospectus included in Mountain Crest Acquisition 6 Corp.’s (the “Registrant”) Registration Statement on Form S-1 (File No. 333-294891) initially filed with the Securities and Exchange Commission on April 6, 2026, as amended from time to time (the “Registration Statement”). This information is incorporated herein by reference. Any form of prospectus or prospectus supplement to the Registration Statement that includes such descriptions and that is filed subsequently to the Registration Statement is hereby also incorporated by reference herein.

Item 2. Exhibits.

Under the Instructions as to Exhibits with respect to Form 8-A, no exhibits are required to be filed 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 l2 of the Securities Exchange Act of 1934, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereto duly authorized.