6-K

UNITED STATESSECURITIES 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 April 2026

Commission File Number: 001-34563

CONCORD MEDICAL SERVICES HOLDINGS LIMITED

Room A1-A5 26/F, East Zone, Hanwei Plaza

No. 7 Guanghua Road, Chaoyang District,

Beijing 100020

People’s Republic of China

(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 x           Form 40-F ¨

Concord Healthcare Files Annual Report on The Stock Exchange ofHong Kong Limited

Concord Healthcare Group Co., Ltd. (“Concord Healthcare”), a subsidiary of Concord Medical Services Holdings Limited (the “Company”) (NYSE: CCM) and a company listed on the Main Board of The Stock Exchange of Hong Kong Limited (the “HKSE”) under the stock code 2453.HK, filed its annual report for the year ended December 31, 2025 on April 15, 2026.

The Company previously announced the listing of Concord Healthcare’s H shares on the HKSE on January 9, 2024. The information related to Concord Healthcare’s annual report on the HKSE is accessible through the HKSE’s website at www.hkexnews.hk.

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.

Date: April 15, 2026