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

March 2020

Commission File Number: 001-37925

GDS Holdings Limited

(Registrant’s name)

2/F, Tower 2, Youyou Century Place

428 South Yanggao Road

Pudong, Shanghai 200127

People’s Republic of 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:

Form 20-F x                      Form 40-F o

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): o

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): o

EXHIBITS

Exhibit 99.1 — GDS to Report Fourth Quarter and Full Year 2019 Financial Results on Thursday, March 19, 2020

2

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.

3

Exhibit 99.1

GDS to Report Fourth Quarter and Full Year 2019 Financial Results on Thursday,

March 19, 2020

SHANGHAI, China, March 05, 2020 (GLOBE NEWSWIRE) — GDS Holdings Limited (“GDS Holdings,” “GDS” or the “Company”) (NASDAQ: GDS), a leading developer and operator of high-performance data centers in China, today announced that it will report its fourth quarter and full year 2019 unaudited financial results on Thursday, March 19, 2020, before the open of the U.S. markets.

The Company’s management will host an earnings conference call at 8:00 AM U.S. Eastern Time on March 19, 2020 (8:00 PM Beijing/Hong Kong time on March 19, 2020).

Dial-in details for the earnings conference call are as follows:

Additionally, a live and archived webcast of the conference call will be available on the Company’s investor relations website at http://investors.gds-services.com.

A replay of the conference call will be accessible by phone approximately two hours after the conclusion of the live call at the following numbers, until March 27, 2020 08:59 AM U.S. ET:

About GDS Holdings Limited

GDS Holdings Limited (Nasdaq: GDS) is a leading developer and operator of high-performance data centers in China. The Company’s facilities are strategically located in China’s primary economic hubs where demand for high-performance data center services is concentrated. The Company’s data centers have large net floor area, high power capacity, density and efficiency, and multiple redundancy across all critical systems. GDS is carrier and cloud neutral, which enables customers to connect directly to all major PRC telecommunications carriers and to the largest PRC and global cloud service providers hosted by GDS in many of its facilities. The Company has a 19-year track record of service delivery, successfully fulfilling the requirements of some of the largest and most demanding customers for outsourced data center services in China. The Company’s base of customers consists predominantly of hyper-scale cloud service providers, large internet companies, financial institutions, telecommunications and IT service providers, and large domestic private sector and multinational corporations.

For investor and media inquiries, please contact:

GDS Holdings Limited

Laura Chen

Phone: +86 (21) 2033-0295

Email: ir@gds-services.com

The Piacente Group, Inc.

Ross Warner

Phone: +86 (10) 6508-0677

Email: GDS@tpg-ir.com

Brandi Piacente

Phone: +1 (212) 481-2050

Email: GDS@tpg-ir.com

GDS Holdings Limited