UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 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

The Joint Corp.

(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), please check the following box.   x

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), check the following.   ¨

Securities Act registration statement number to which the form relates: 333-198860

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

The Joint Corp. (the “Registrant”) hereby incorporates by reference the description of its common stock, par value $0.001 per share, to be registered hereunder contained under the heading “Description of Capital Stock” in the Registrant’s Registration Statement on Form S-1 (File No. 333-198860), as originally filed with the Securities and Exchange Commission (the “Commission”) on September 19, 2014, as subsequently amended (as amended, the “Registration Statement”). Any form of prospectus subsequently filed by the Registrant with the Commission pursuant to Rule 424(b) under the Securities Act of 1933, as amended, that constitutes part of the Registration Statement shall be deemed to be incorporated by reference herein.

Pursuant to 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, the Company has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized.