6-K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 OF THE

SECURITIES EXCHANGE ACT OF 1934

For the month of November 2021

Commission File Number 001-40469

AcuityAds Holdings Inc.

(Translation of registrant’s name into English)

70 University Ave., Suite 1200

Toronto, Ontario

M5J 2M4

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ¨

DOCUMENTS INCLUDED AS PART OF THIS REPORT

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Exhibit 99.1

AcuityAds Appoints Elliot Muchnik As Chief FinancialOfficer

TORONTO and NEW YORK – November 30, 2021 – AcuityAds Holdings Inc. (TSX:AT, Nasdaq:ATY) (“AcuityAds” or the “Company”), a digital advertising technology leader that provides targeted media solutions enabling advertisers to connect intelligently with audiences across advertising channels, today announced the appointment of Elliot Muchnik, CPA, CA as Chief Financial Officer.

Mr. Muchnik joins AcuityAds from Richardson Wealth Limited, one of Canada’s largest, regulated independent wealth management firms with over $35 billion in assets under administration, where he served as Chief Financial Officer and Corporate Secretary since 2007. During his tenure with Richardson Wealth, Mr. Muchnik helped lead the company to exponential revenue growth. Previously, he was a Senior Vice President and Managing Director at BMO Nesbitt Burns. Mr. Muchnik holds a Bachelor of Business Administration from York University.

Mr. Muchnik will succeed Tatiana Kresling, who has served as the Company’s Interim Chief Financial Officer since September 2021.

“On behalf of the entire AcuityAds team, I welcome Elliot as our CFO and look forward to his contributions,” said Tal Hayek, Co-Founder and Chief Executive Officer of AcuityAds. “His extensive financial, operational and M&A experience make him the ideal choice to help drive AcuityAds’ continued growth and profitability as we continue to advance our illumin platform, which is revolutionizing the programmatic advertising industry. I would also like to recognize and thank Tatiana for her outstanding work as Interim CFO.”

About AcuityAds:

AcuityAds is a leading technology company that provides marketers a one-stop solution for omnichannel digital advertising with best-of-category return on advertising spend. Its journey automation technology, illumin™, offers planning, buying and real-time intelligence from one platform. With proprietary Artificial Intelligence, illumin™ brings unique programmatic capabilities to close the gap between advertising planning and execution. The Company brings an integrated ecosystem of privacy-protected data, inventory, brand safety and fraud prevention partners, offering trusted solutions with proven, above-benchmark outcomes for the most demanding marketers.

AcuityAds is headquartered in Toronto with offices throughout Canada, the U.S., Europe and Latin America. For more information, visit AcuityAds.com.

For further information, please contact

Disclaimer in regard to Forward-lookingStatements

Certain statements included herein constitute “forward-looking statements” within the meaning of applicable securities laws. Forward-looking statements are necessarily based upon a number of estimates and assumptions that, while considered reasonable by management at this time, are inherently subject to significant business, economic and competitive uncertainties and contingencies.  Investors are cautioned not to put undue reliance on forward-looking statements.  Except as required by law, AcuityAds does not intend, and undertakes no obligation, to update any forward-looking statements to reflect, in particular, new information or future events.