6-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 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 May, 2026

Commission File Number: 333-249081

Curaleaf Holdings, Inc. (Name of Registrant)

666 Burrard Street, Suite 1700,

Vancouver, British Columbia V6C 2X8, Canada (Address of Principal Executive Office)

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 ☐    Form 40-F ☒

SIGNATURE

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 INDEX

cura-noticeofchangeofaud

CURALEAF HOLDINGS, INC. (the “Corporation”) NOTICE OF CHANGE OF AUDITOR (the “Notice”) To: PKF O’Connor Davies, LLP And To: BDO USA, P.C. RE: Notice Regarding Change of Auditor Pursuant to Section 4.11 of National Instrument 51- 102 – Continuous Disclosure Obligations (“NI 51-102”) Curaleaf Holdings, Inc. (the “Company”) hereby gives notice pursuant to Section 4.11 of NI 51-102 as follows: 1. At the request of the Company, PKF O’Connor Davies, LLP (the “Former Auditor”), will be resigning as the Company’s independent auditor effective May 6, 2026 (the “Effective Date”). 2. On the Effective Date, the Company will appoint BDO USA, P.C. (the “Successor Auditor”) to fill the vacancy created by the resignation of the Former Auditor, and to hold such position until the close of the next annual meeting of shareholders of the Company. 3. The resignation of the Former Auditor as auditor of the Company and the appointment of the Successor Auditor as auditor of the Company were considered and approved by the Board of Directors of the Company. 4. The Former Auditor has not expressed any modified opinion in its reports for the Company’s two (2) most recently completed fiscal years or for any period subsequent to the most recently completed period for which an audit report was issued and preceding the Effective Date. 5. In the opinion of the Board of Directors of the Corporation, no “reportable event” as defined in NI 51-102 has occurred since the date of the Former Auditor’s appointment. DATED May 5, 2026 CURALEAF HOLDINGS, INC. Per: “Ed Kremer” Ed Kremer Chief Financial Officer

cura-formerauditorletter

PKF O’CONNOR DAVIES, LLP 245 Park Avenue, New York, NY 10167 I Tel: 212.867.8000 or 212.286.2600 I Fax: 212.286.4080 I www.pkfod.com PKF O’Connor Davies, LLP is a member firm of the PKF International Limited network of legally independent firms and does not accept any responsibility or liability for the actions or inactions on the part of any other individual member firm or firms. May 6, 2026 British Columbia Securities Commission Alberta Securities Commission Financial and Consumer Affairs Authority of Saskatchewan The Manitoba Securities Commission Ontario Securities Commission Autorité des marchés financiers (Québec) Financial and Consumer Services Commission (New Brunswick) Nova Scotia Securities Commission Financial and Consumer Services Division (Prince Edward Island) Office of the Superintendent of Securities Service, Newfoundland and Labrador Office of the Yukon Superintendent of Securities Office of the Superintendent of Securities (Northwest Territories) Office of the Superintendent of Securities, Nunavut Dear Sirs/Mesdames: Re: Curaleaf Holdings, Inc. – Change of Auditor Pursuant to National Instrument 51-102 – Continuous Disclosure Obligations, we have reviewed the information contained in the Notice of Change of Auditor of Curaleaf Holdings, Inc. dated May 5, 2026 (the "Notice") and, based on our knowledge of such information at this time, we agree with the statements made in the Notice. Yours very truly, PKF O’Connor Davies, LLP New York, New York

curaleafholdingsinc2026s

BDO USA refers to BDO USA, P.C., a Virginia professional corporation, also doing business in certain jurisdictions with an alternative identifying abbreviation, such as Corp. or P.S.C. BDO USA, P.C. is the U.S. member of BDO International Limited, a UK company limited by guarantee, and forms part of the international BDO network of independent member firms. BDO is the brand name for the BDO network and for each of the BDO Member Firms. 109 Michigan St. NW, Suite 640 Grand Rapids, MI 49503 Tel: 616-774-7000 Fax: 616-776-3680 www.bdo.com May 6, 2026 British Columbia Securities Commission Alberta Securities Commission Financial and Consumer Affairs Authority of Saskatchewan The Manitoba Securities Commission Ontario Securities Commission Autorité des marchés financiers (Québec) Financial and Consumer Services Commission (New Brunswick) Nova Scotia Securities Commission Financial and Consumer Services Division (Prince Edward Island) Office of the Superintendent of Securities Service, Newfoundland and Labrador Office of the Yukon Superintendent of Securities Office of the Superintendent of Securities (Northwest Territories) Office of the Superintendent of Securities, Nunavut Dear Sirs/Mesdames: Re: Curaleaf Holdings, Inc. – Change of Auditor Pursuant to National Instrument 51-102 – Continuous Disclosure Obligations, we have reviewed the information contained in the Notice of Change of Auditor of Curaleaf Holdings, Inc. dated May 5, 2026 (the “Notice”) and, based on our knowledge of such information at this time, we agree with the statements made in the Notice pertaining to our firm. Yours very truly, Grand Rapids, Michigan