U.S. SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the month of June 2021

Commission File Number: 001-36885

Tantech Holdings Ltd

(Registrant’s name)

c/o Zhejiang Forest Bamboo Technology Co., Ltd.

No. 10 Cen Shan Road, Shuige Industrial Zone

Lishui City, Zhejiang Province 323000

+86-578-226-2305

(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.

Form 20-F x          Form 40-F ¨

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

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

Explanatory Note:

The Registrant is filing this Report on Form 6-K to provide its proxy statement for its 2021 annual shareholder meeting.

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.