Exhibit 8.1

Simpson Thacher & Bartlett LLP

425 LEXINGTON AVENUE

NEW YORK, NY 10017-3954

TELEPHONE: +1-212-455-2000

FACSIMILE: +1-212-455-2502

October 4, 2016

GDS Holdings Limited

2/F, Tower 2, Youyou Century Place

428 South Yanggao Road

Pudong Shanghai 200127

People’s Republic of China

Ladies and Gentlemen:

We have acted as United States counsel to GDS Holdings Limited, a Cayman Islands company (the “Company”), in connection with the registration statement on Form F-1, including the prospectus contained therein (together, the “Registration Statement”), filed on the date hereof by the Company with the U.S. Securities and Exchange Commission (the “Commission”) under the U.S. Securities Act of 1933, as amended, relating to the registration of shares of the Company’s ordinary shares, par value US$0.00005 per share, which will be represented by American depositary shares (“ADSs”) evidenced by American depositary receipts.

We have examined the Registration Statement and the form of deposit agreement to be entered into among the Company, JPMorgan Chase Bank, N.A., as depositary and holders from time to time of ADSs (the “Deposit Agreement”). In addition, we have examined, and have relied as to matters of fact upon, originals, or duplicates or certified or conformed copies, of such records, agreements, documents and other instruments and such certificates or comparable documents of public officials and of officers and representatives of the Company, and have made such other and further investigations as we have deemed necessary or appropriate as a basis for the opinion hereinafter set forth. In such examination, we have assumed the accuracy of the factual matters described in the Registration Statement and that the Registration Statement and other documents will be executed by the parties in the forms provided to and reviewed by us. We have also assumed that the Deposit Agreement is executed in the form reviewed by us.

BEIJING

HONG KONG

HOUSTON

LONDON

LOS ANGELES

PALO ALTO

SÃO PAULO

SEOUL

TOKYO

WASHINGTON, D.C.

In rendering the opinion set forth below, we have assumed the genuineness of all signatures, the legal capacity of natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as duplicates or certified or conformed copies and the authenticity of the originals of such latter documents.

Based upon the foregoing, and subject to the qualifications, assumptions and limitations stated herein and in the Registration Statement, we hereby confirm that the discussion set forth on pages 201-206 of the Registration Statement under the caption “Taxation — Material United States Federal Income Tax Considerations,” insofar as such discussion relates to matters of United States federal income tax law, constitutes our opinion as to the material United States federal income tax consequences to United States Holders (as such term is defined in the Registration Statement) of the purchase, ownership and disposition of the Company’s ADSs and ordinary shares.

We note that, because the determination of the Company’s status as a passive foreign investment company (a “PFIC”) for United States federal income tax purposes is based on an annual determination that cannot be made until the close of a taxable year, and involves extensive factual investigation, we do not express any opinion herein with respect to the Company’s PFIC status in any taxable year.

We do not express any opinion herein concerning any law other than the United States federal income tax law.

We hereby consent to the filing of this opinion with the Commission as an exhibit to the Registration Statement and to the reference to our firm under the headings “Taxation” and “Legal Matters” in the Registration Statement.

	Very truly yours,
	/s/ Simpson Thacher & Bartlett LLP
	SIMPSON THACHER & BARTLETT LLP