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

November 2025

Commission File Number: 001-37925

GDS HoldingsLimited

(Registrant’s name)

F4/F5, Building C, Sunland International

No. 999 Zhouhai Road

Pudong, Shanghai 200137

People’s Republic of China

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annualreports under cover of Form 20-F or Form 40-F:

Form 20-Fx Form 40-F ¨

EXHIBITS

SIGNATURES

Pursuant to the requirementsof the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereuntoduly authorized.

Exhibit 99.1

GDS Reports

Third Quarter2025 Results

GDS Holdings Limited Reports Third Quarter 2025Results

Shanghai, China, November 19, 2025 – GDS Holdings Limited (“GDS Holdings”, “GDS” or the “Company”) (NASDAQ: GDS; HKEX: 9698), aleading developer and operator of high-performance data centers in China, today announced its unaudited financial results for the thirdquarter ended September 30, 2025.

Third Quarter 2025 Financial Highlights

Third Quarter 2025 Operating Highlights

“We delivered another quarter of solid financialand operational performance, driven by our disciplined strategic execution,” stated Mr. William Huang, Chairman and CEO ofGDS. “In the third quarter of 2025, we continued to deliver our backlog and achieved a high level of move-in. We are strategicallypositioned to capture the accelerating demand from AI, which we view as a significant, long-term growth catalyst for our business.”

“In the third quarter of 2025, our revenueincreased by 10.2% and adjusted EBITDA grew by 11.4% year-over-year, delivering an adjusted EBITDA margin of 46.5%,” added Mr. DanNewman, Chief Financial Officer. “With enhanced financial flexibility to support our next phase of growth, we remain dedicated todelivering sustainable, long-term value for our stakeholders.”

Third Quarter 2025 Financial Results

Net revenue in the third quarter of 2025 was RMB2,887.1million (US$405.6 million), a 10.2% increase over the same period last year of RMB2,619.6 million. The Y-o-Y increase was mainly due tocontinued ramp-up of our data centers.

Cost of revenue in the third quarter of 2025 wasRMB2,247.9 million (US$315.8 million), a 9.0% increase over the same period last year of RMB2,062.0 million. The Y-o-Y increase was inline with the continued ramp-up of our data centers.

Gross profit was RMB639.2 million (US$89.8 million)in the third quarter of 2025, a 14.6% increase over the same period last year of RMB557.6 million.

Gross profit margin was 22.1% in the third quarterof 2025, compared with 21.3% in the same period last year. The Y-o-Y increase was mainly due to a lower level of operating costs as apercentage of net revenue as our data centers continue to ramp up.

Adjusted Gross Profit (“Adjusted GP”)(non-GAAP) is defined as gross profit excluding depreciation and amortization, operating lease cost relating to prepaid land use rights,accretion expenses for asset retirement costs and share-based compensation expenses allocated to cost of revenue. Adjusted GP was RMB1,472.6million (US$206.8 million) in the third quarter of 2025, a 11.3% increase over the same period last year of RMB1,323.0 million. See “Non-GAAPDisclosure” and “Reconciliations of GAAP and non-GAAP results” elsewhere in this earnings release.

Adjusted GP margin (non-GAAP) was 51.0% in thethird quarter of 2025, compared with 50.5% in the same period last year. The Y-o-Y increase was mainly due to a lower level of cash operatingcosts as a percentage of net revenue as our data centers continue to ramp up.

Selling and marketing expenses, excluding share-basedcompensation expenses of RMB9.1 million (US$1.3 million), were RMB31.1 million (US$4.4 million) in the third quarter of 2025, a 24.2%increase over the same period last year of RMB25.1 million (excluding share-based compensation of RMB7.3 million). The Y-o-Y increasewas mainly due to higher sales-related personnel costs.

General and administrative expenses, excludingshare-based compensation expenses of RMB43.8 million (US$6.2 million), depreciation and amortization expenses of RMB59.9 million (US$8.4million) and operating lease cost relating to prepaid land use rights of RMB15.5 million (US$2.2 million), were RMB109.2 million (US$15.3million) in the third quarter of 2025, a 15.5% increase over the same period last year of RMB94.5 million (excluding share-based compensationexpenses of RMB30.2 million, depreciation and amortization expenses of RMB70.6 million and operating lease cost relating to prepaid landuse rights of RMB16.1 million). The Y-o-Y increase was mainly due to an increase in corporate expenses in line with business growth.

Research and development costs were RMB8.3 million(US$1.2 million) in the third quarter of 2025, compared with RMB8.6 million in the same period last year.

Net interest expenses for the third quarter of2025 were RMB375.5 million (US$52.7 million), a 19.0% decrease over the same period last year of RMB463.3 million. The Y-o-Y decreasewas mainly due to a lower level of total borrowings, lower interest rates and higher interest income earned on cash proceeds from ourrecent capital market transactions.

Foreign currency exchange loss for the third quarterof 2025 was RMB0.6 million (US$0.1 million), compared with foreign currency exchange gain of RMB0.6 million in the same period last year.

Others, net for the third quarter of 2025 was RMB16.1 million (US$2.3 million), compared with RMB5.0 million in the same period last year.

Gain on deconsolidation of subsidiaries for thethird quarter of 2025 was RMB1,369.3 million (US$192.3 million), mainly arising from deconsolidation of the data center project companieswhich were sold to the C-REIT, compared to nil in the same period last year.

Income tax expenses for the third quarter of 2025were RMB181.9 million (US$25.5 million), compared with income tax benefits of RMB0.3 million in the same period last year. The Y-o-Y increasewas mainly due to the income tax expenses incurred for the C-REIT transaction.

Share of results of equity method investees forthe third quarter of 2025 was a loss of RMB461.1 million (US$64.8 million), mainly arising from our investment in DayOne Data CentersLimited, compared with nil in the same period last year.

Net income in the third quarter of 2025 was RMB728.6million (US$102.4 million), compared with net loss of RMB231.1 million in the same period last year. The Y-o-Y increase was mainly dueto the gain on deconsolidation of subsidiaries arising from the C-REIT transaction.

Basic income per ordinary share in the third quarterof 2025 was RMB0.46 (US$0.06), compared with basic loss of RMB0.14 in the same period last year. Diluted income per ordinary share inthe third quarter of 2025 was RMB0.40 (US$0.06), compared with diluted loss of RMB0.14 in the same period last year.

Basic income per American Depositary Share (“ADS”)in the third quarter of 2025 was RMB3.70 (US$0.52), compared with basic loss of RMB1.12 in the same period last year. Diluted income perADS in the third quarter of 2025 was RMB3.21 (US$0.45), compared with diluted loss of RMB1.12 in the same period last year.

Adjusted EBITDA (non-GAAP) is defined as net income(loss) excluding income (loss) from discontinued operations, net interest expenses, income tax expenses (benefits), depreciation and amortization,operating lease cost relating to prepaid land use rights, accretion expenses for asset retirement costs, share-based compensation expenses,gain from purchase price adjustment, impairment losses of long-lived assets, share of results of equity method investees and gain on deconsolidationof subsidiaries. Adjusted EBITDA was RMB1,342.2 million (US$188.5 million) in the third quarter of 2025, a 11.4% increase over the sameperiod last year of RMB1,204.9 million.

Adjusted EBITDA margin (non-GAAP) was 46.5% inthe third quarter of 2025, compared with 46.0% in the same period last year. The Y-o-Y increase was mainly due to a lower level of cashoperating costs and corporate expenses as a percentage of net revenue as our data centers continue to ramp up.

Liquidity

As of September 30, 2025, cash was RMB13,443.7million (US$1,888.4 million).

Total short-term debt was RMB3,312.6 million (US$465.3million), comprised of short-term borrowings and the current portion of long-term borrowings of RMB2,634.9 million (US$370.1 million)and the current portion of finance lease and other financing obligations of RMB677.7 million (US$95.2 million). Total long-term debt wasRMB42,324.5 million (US$5,945.3 million), comprised of long-term borrowings (excluding current portion) of RMB22,916.8 million (US$3,219.1million), the non-current portion of convertible bonds payable of RMB12,265.4 million (US$1,722.9 million) and the non-current portionof finance lease and other financing obligations of RMB7,142.2 million (US$1,003.3 million).

During the third quarter of 2025, the Companyobtained new debt financing and refinancing facilities of RMB5,053.8 million (US$709.9 million).

Completion of C-REIT IPO and Listing on the Shanghai Stock Exchange

During the third quarter, the Company completedits China REIT (C-REIT) initial public offering (“IPO”). The C-REIT started trading on the Shanghai Stock Exchange on August8, 2025 under fund code 508060. As of the close of business on November 18, 2025, the C-REIT was trading at a 45.8% premium to the IPOprice, with an implied EV / EBITDA multiple of 24.6 times, and an implied dividend yield of 3.6 per cent.

On completion of the transaction, during the thirdquarter, GDS received cash consideration of RMB2,247.9 million (US$315.8 million) (net of transaction costs) as investment cash inflow.GDS also paid RMB480.0 million (US$67.4 million) for the subscription of 20% of the C-REIT as investment cash outflow.

Third Quarter 2025 Operating Results

Sales

Total area committed and pre-committed at theend of the third quarter of 2025 was 656,729 sqm, compared with 626,783 sqm at the end of the third quarter of 2024 and 663,959 sqm atthe end of the second quarter of 2025, an increase of 4.8% Y-o-Y and a decrease of 1.1% quarter-over-quarter (“Q-o-Q”), respectively.In the third quarter of 2025, gross additional total area committed was 11,104 sqm. Net additional total area committed was negative 7,231sqm. The difference was mainly due to a churn of 3,154 sqm and the deconsolidation of the underlying projects for the C-REIT transactionof 15,181 sqm.

Data Center Resources

Area in service at the end of the third quarterof 2025 was 653,762 sqm, compared with 595,606 sqm at the end of the third quarter of 2024 and 618,060 sqm at the end of the second quarterof 2025, an increase of 9.8% Y-o-Y and 5.8% Q-o-Q. The Q-o-Q increase of 35,701 sqm was due to data centers newly in service of 50,882sqm, partially offset by the deconsolidation of the underlying projects for the C-REIT transaction of 15,181 sqm.

Area under construction at the end of the thirdquarter of 2025 was 72,764 sqm, compared with 120,422 sqm at the end of the third quarter of 2024 and 132,235 sqm at the end of the secondquarter of 2025, a decrease of 39.6% Y-o-Y and 45.0% Q-o-Q, respectively. The Q-o-Q decrease was mainly due to data centers coming intoservice.

Commitment rate for area in service was 92.3%at the end of the third quarter of 2025, compared with 92.1% at the end of the third quarter of 2024 and 91.5% at the end of the secondquarter of 2025. Pre-commitment rate for area under construction was 73.0% at the end of the third quarter of 2025, compared with 65.1%at the end of the third quarter of 2024 and 74.7% at the end of the second quarter of 2025.

Move-In

Area utilized at the end of the third quarterof 2025 was 486,607 sqm, compared with 438,654 sqm at the end of the third quarter of 2024 and 479,186 sqm at the end of the second quarterof 2025, an increase of 10.9% Y-o-Y and 1.5% Q-o-Q. In the third quarter of 2025, gross additional area utilized was 23,291 sqm. Net additionalarea utilized was 7,421 sqm. The difference was mainly due to churn of 1,254 sqm and the deconsolidation of the underlying projects forthe C-REIT transaction of 14,616 sqm.

Utilization rate for area in service was 74.4%at the end of the third quarter of 2025, compared with 73.6% at the end of the third quarter of 2024 and 77.5% at the end of the secondquarter of 2025. The Q-o-Q temporary decrease was mainly because of the data centers newly in service, including all of the underlyingdata centers for the 152MW hyperscale order we won in the first quarter of 2025.

Business Outlook

The Company confirms that the previously providedguidance of total revenues for the year of 2025 of RMB11,290 – RMB11,590 million, Adjusted EBITDA of RMB5,190 – RMB5,390 millionand the revised capex guidance of approximately RMB2,700 million remain unchanged.

This forecast reflects the Company’s preliminaryview on the current business situation and market conditions, which are subject to change.

Conference Call

Management will hold a conference call at 8:00a.m. U.S. Eastern Time on November 19, 2025 (9:00 p.m. Beijing Time on November 19, 2025) to discuss financial resultsand answer questions from investors and analysts.

Participants should complete online registrationusing the link provided below at least 15 minutes before the scheduled start time. Upon registration, participants will receive the conferencecall access information, including dial-in numbers, a personal PIN and an e-mail with detailed instructions to join the conference call.

Participant Online Registration:

https://register-conf.media-server.com/register/BIbc621387c7464640a6c8fbcb918b40bc

A live and archived webcast of the conferencecall will be available on the Company’s investor relations website at investors.gds-services.com.

Non-GAAP Disclosure

Our management and board of directors use AdjustedEBITDA, Adjusted EBITDA margin, Adjusted GP and Adjusted GP margin, which are non-GAAP financial measures, to evaluate our operating performance,establish budgets and develop operational goals for managing our business. We believe that the exclusion of the income and expenses eliminatedin calculating Adjusted EBITDA and Adjusted GP can provide useful and supplemental measures of our core operating performance. In particular,we believe that the use of Adjusted EBITDA as a supplemental performance measure captures the trend in our operating performance by excludingfrom our operating results the impact of our capital structure (primarily interest expense), asset base charges (primarily depreciationand amortization, operating lease cost relating to prepaid land use rights, accretion expenses for asset retirement costs and impairmentlosses of long-lived assets), other non-cash expenses (primarily share-based compensation expenses), and other income and expenses whichwe believe are not reflective of our operating performance (primarily gain or loss on deconsolidation of subsidiaries and share of resultsof equity method investees), whereas the use of adjusted gross profit as a supplemental performance measure captures the trend in grossprofit performance of our data centers in service by excluding from our gross profit the impact of asset base charges (primarily depreciationand amortization, operating lease cost relating to prepaid land use rights and accretion expenses for asset retirement costs) and othernon-cash expenses (primarily share-based compensation expenses) included in cost of revenue. In addition, we exclude the income (loss)from discontinued operations from our Adjusted EBITDA and Adjusted EBITDA margin to measure our financial performance from continuing operations,which will be consistent with our future financial performance disclosure.

We note that depreciation and amortization isa fixed cost which commences as soon as each data center enters service. However, it usually takes several years for new data centersto reach high levels of utilization and profitability. The Company incurs significant depreciation and amortization costs for its earlystage data center assets. Accordingly, gross profit, which is a measure of profitability after taking into account depreciation and amortization,does not accurately reflect the Company’s core operating performance.

We also present these non-GAAP measures becausewe believe these non-GAAP measures are frequently used by securities analysts, investors and other interested parties as measures of thefinancial performance of companies in our industry.

These non-GAAP financial measures are not definedunder U.S. GAAP and are not presented in accordance with U.S. GAAP. These non-GAAP financial measures have limitations as analytical tools,and when assessing our operating performance, cash flows or our liquidity, investors should not consider them in isolation, or as a substitutefor gross profit, net income (loss), cash flows provided by (used in) operating activities or other consolidated statements of operationsand cash flow data prepared in accordance with U.S. GAAP. There are a number of limitations related to the use of these non-GAAP financialmeasures instead of their nearest GAAP equivalent. First, Adjusted EBITDA, Adjusted EBITDA margin, Adjusted GP, and Adjusted GP marginare not substitutes for gross profit, net income (loss), cash flows provided by (used in) operating activities or other consolidated statementsof operation and cash flow data prepared in accordance with U.S. GAAP. Second, other companies may calculate these non-GAAP financialmeasures differently or may use other measures to evaluate their performance, all of which could reduce the usefulness of these non-GAAPfinancial measures as tools for comparison. Finally, these non-GAAP financial measures do not reflect the impact of income (loss) fromdiscontinued operations, net interest expenses, incomes tax benefits (expenses), depreciation and amortization, operating lease cost relatingto prepaid land use rights, accretion expenses for asset retirement costs, share-based compensation expenses, gain from purchase priceadjustment, impairment losses of long-lived assets, gain on deconsolidation of subsidiaries and share of results of equity method investees,each of which have been and may continue to be incurred in our business.

We mitigate these limitations by reconciling thenon-GAAP financial measure to the most comparable U.S. GAAP performance measure, all of which should be considered when evaluating ourperformance. We do not provide forward-looking guidance for certain financial data, such as depreciation, amortization, accretion, share-basedcompensation, share of results of equity method investees and net income (loss); the impact of such data and related adjustments can besignificant. As a result, we are not able to provide a reconciliation of forward-looking U.S. GAAP to forward-looking non-GAAP financialmeasures without unreasonable effort. Such forward-looking non-GAAP financial measures include the forecast for Adjusted EBITDA in thesection captioned “Business Outlook” set forth in this press release.

For more information on these non-GAAP financialmeasures, please see the table captioned “Reconciliations of GAAP and non-GAAP results” set forth at the end of this pressrelease.

Exchange Rate

This announcement contains translations of certainRMB amounts into U.S. dollars (“USD”) at specified rates solely for the convenience of the reader. Unless otherwise stated,all translations from RMB to USD were made at the rate of RMB7.1190 to US$1.00, the noon buying rate in effect on September 30, 2025in the H.10 statistical release of the Federal Reserve Board. The Company makes no representation that the RMB or USD amounts referredcould be converted into USD or RMB, as the case may be, at any particular rate or at all.

Statement Regarding Preliminary UnauditedFinancial Information

The unaudited financial information set out inthis earnings release is preliminary and subject to potential adjustments. Adjustments to the consolidated financial statements may beidentified when audit work has been performed for the Company’s year-end audit, which could result in significant differences fromthis preliminary unaudited financial information.

About GDS Holdings Limited

GDS Holdings Limited (NASDAQ: GDS; HKEX: 9698)is a leading developer and operator of high-performance data centers in China. The Company’s facilities are strategically locatedin and around primary economic hubs where demand for high-performance data center services is concentrated. The Company’s data centershave large net floor area, high power capacity, density and efficiency, and multiple redundancies across all critical systems. GDS iscarrier and cloud-neutral, which enables its customers to access the major telecommunications networks, as well as the largest PRC andglobal public clouds, which are hosted in many of its facilities. The Company offers co-location and a suite of value-added services,including managed hybrid cloud services through direct private connection to leading public clouds, managed network services, and, whererequired, the resale of public cloud services. The Company has a 24-year track record of service delivery, successfully fulfilling therequirements of some of the largest and most demanding customers for outsourced data center services in China. The Company’s customerbase consists predominantly of hyperscale cloud service providers, large internet companies, financial institutions, telecommunicationscarriers, IT service providers, and large domestic private sector and multinational corporations. The Company also holds a non-controlling35.6% equity interest in DayOne Data Centers Limited which develops and operates data centers in international markets.

Safe Harbor Statement

This announcement contains forward-looking statements.These statements are made under the “safe harbor” provisions of the U.S. Private Securities Litigation Reform Act of 1995.These forward-looking statements can be identified by terminology such as “aim,” “anticipate,” “believe,” “continue,” “estimate,” “expect,” “future,” “guidance,” “intend,” “is/are likely to,” “may,” “ongoing,” “plan,” “potential,” “target,” “will,” and similar statements. Among other things, statements that are not historical facts, including statements about GDSHoldings’ beliefs and expectations regarding the growth of its businesses and its revenue for the full fiscal year, the businessoutlook and quotations from management in this announcement, as well as GDS Holdings’ strategic and operational plans, are or containforward-looking statements. GDS Holdings may also make written or oral forward-looking statements in its periodic reports to the U.S.Securities and Exchange Commission (the “SEC”) on Forms 20-F and 6-K, in its current, interim and annual reports to shareholders,in announcements, circulars or other publications made on the website of the Stock Exchange of Hong Kong Limited (the “Hong KongStock Exchange”), in press releases and other written materials and in oral statements made by its officers, directors or employeesto third parties. Forward-looking statements involve inherent risks and uncertainties. A number of factors could cause GDS Holdings’actual results or financial performance to differ materially from those contained in any forward-looking statement, including but notlimited to the following: GDS Holdings’ goals and strategies; GDS Holdings’ future business development, financial conditionand results of operations; the expected growth of the market for high-performance data centers, data center solutions and related servicesin China and regions in which GDS Holdings’ major equity investees operate, such as South East Asia; GDS Holdings’ expectationsregarding demand for and market acceptance of its high-performance data centers, data center solutions and related services; GDS Holdings’expectations regarding building, strengthening and maintaining its relationships with new and existing customers; the results of operations,growth prospects, financial condition, regulatory environment, competitive landscape and other uncertainties associated with the businessand operations of GDS Holdings’ major equity investee DayOne; the continued adoption of cloud computing and cloud service providersin China and other major markets that may impact the results of our equity investees, such as South East Asia; risks and uncertaintiesassociated with increased investments in GDS Holdings’ business and new data center initiatives; risks and uncertainties associatedwith strategic acquisitions and investments; GDS Holdings’ ability to maintain or grow its revenue or business; fluctuations inGDS Holdings’ operating results; changes in laws, regulations and regulatory environment that affect GDS Holdings’ businessoperations and those of its major equity investees; competition in GDS Holdings’ industry in China and in markets that affect thebusiness operations of its major equity investees, such as South East Asia; GDS Holdings’ ability to monetize its existing datacenter assets through transactions such as public REITs, ABS Schemes, data center funds, joint ventures, sale and lease-back arrangementsand private asset sales; security breaches; power outages; and fluctuations in general economic and business conditions in China and globally,and assumptions underlying or related to any of the foregoing. Further information regarding these and other risks, uncertainties or factorsis included in GDS Holdings’ filings with the SEC, including its annual report on Form 20-F, and with the Hong Kong Stock Exchange.All information provided in this press release is as of the date of this press release and are based on assumptions that GDS Holdingsbelieves to be reasonable as of such date, and GDS Holdings does not undertake any obligation to update any forward-looking statement,except as required under applicable law.

For investor and media inquiries, please contact:

GDS Holdings Limited

Laura Chen

Phone: +86 (21) 2029-2203

Email: ir@gds-services.com

Piacente Financial Communications

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

GDS HOLDINGS LIMITED

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS

(Amount in thousands of Renminbi (“RMB”)and US dollars (“US$”))

GDS HOLDINGS LIMITED

UNAUDITED CONDENSED CONSOLIDATED STATEMENTSOF OPERATIONS

(Amount in thousands of Renminbi (“RMB”)and US dollars (“US$”)

except for number of shares and per share data)

GDS HOLDINGS LIMITED

UNAUDITED CONDENSED CONSOLIDATED STATEMENTSOF COMPREHENSIVE (LOSS) INCOME

(Amount in thousands of Renminbi (“RMB”)and US dollars (“US$”))

GDS HOLDINGS LIMITED

UNAUDITED CONDENSED CONSOLIDATED STATEMENTSOF CASH FLOWS

(Amount in thousands of Renminbi (“RMB”)and US dollars (“US$”))

GDS HOLDINGS LIMITED

RECONCILIATIONS OF GAAP AND NON-GAAP RESULTS

(Amount in thousands of Renminbi (“RMB”)and US dollars (“US$”)

except for percentage data)

GDS HOLDINGS LIMITED

RECONCILIATIONS OF GAAP AND NON-GAAP RESULTS

(Amount in thousands of Renminbi (“RMB”)and US dollars (“US$”)

except for percentage data)