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 September 2026

Commission File Number: 001-41658

Lucas GC Limited

(Exact name of registrant as specified in its charter)

Room 1109, 11/F, Tower A

Star Plaza, No. 8 Wangjing Street

Chaoyang District

Beijing 100102, China

(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.

EXPLANATORY NOTE

This report on Form 6-K and the attached Exhibits 99.1 and 99.2 are incorporated by reference into the Company’s registration statement on Form F-3 (SEC File No. 333-286651) and Form S-8 (SEC File No. 333-283728), as amended, and into each prospectus and prospectus supplement under the foregoing registration statements, to the extent not superseded by documents or reports subsequently filed or furnished by the Company under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended.

Exhibits Index

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.

Date: September 18, 2026