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

October 2017

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 — Press release – GDS to Report Third Quarter 2017 Financial Results on Thursday, November 9, 2017

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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 Third Quarter 2017 Financial Results on Thursday, November 9, 2017

SHANGHAI, China, October 26, 2017 (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 third quarter 2017 unaudited financial results on Thursday, November 9, 2017, 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 November 9, 2017 (9:00 PM Beijing/Hong Kong time on November 9, 2017).

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 November 16, 2017:

About GDS Holdings Limited

GDS Holdings Limited (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 to all major PRC telecommunications carriers, and to access a number of the largest PRC cloud service providers, whom GDS hosts in its facilities. The Company offers colocation and managed services, including a unique and innovative managed cloud value proposition. The Company has a 16-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 hyperscale 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) 5730-6200 
Email: GDS@tpg-ir.com

Alan Wang 
Phone: +1 (212) 481-2050 ext. 401 
Email: GDS@tpg-ir.com