UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G/A

(Amendment No. 1)*

Under the Securities Exchange Act of 1934

Endurance International Group Holdings, Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Titles of Class of Securities)

29272B105

(CUSIP Number)

December 31, 2014

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

¨ Rule 13d-1(b)

¨ Rule 13d-1(c)

x Rule 13d-1(d)

The information required in the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”) or otherwise subject to the liabilities of that section of the Exchange Act but shall be subject to all other provisions of the Exchange Act (however, see the Notes).

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The name of the issuer is Endurance International Group Holdings, Inc., a Delaware corporation (the “Issuer”).

The principal executive offices of the Issuer are located at 10 Corporate Drive, Suite 300, Burlington, Massachusetts 01803.

This Schedule 13G/A is being filed jointly by (i) Warburg Pincus Private Equity X, L.P., a Delaware limited partnership (“WP X”), (ii) Warburg Pincus X Partners, L.P., a Delaware limited partnership (together with WP X, the “WP X Funds”), (iii) WP Expedition Co-Invest L.P., a Delaware limited partnership (“WP Co-Invest”), (iv) Warburg Pincus X, L.P., a Delaware limited partnership (“WP X LP”), the general partner of the WP X Funds, (v) Warburg Pincus X GP L.P., a Delaware limited partnership (“WP X GP”), the general partner of WP X LP, (vi) WPP GP LLC, a Delaware limited liability company (“WPP GP”), the general partner of WP X GP, (vii) Warburg Pincus Partners, L.P., a Delaware limited partnership (“WP Partners”), the managing member of WPP GP and the general partner of WP Co-Invest, (viii) Warburg Pincus Partners GP LLC, a Delaware limited liability company (“WP Partners GP”), the general partner of WP Partners, (ix) Warburg Pincus & Co., a New York general partnership (“WP”), the managing member of WP Partners GP, (x) Warburg Pincus LLC, a New York limited liability company (“WP LLC”), the manager of the WP X Funds, and (xi) Messrs. Charles R. Kaye and Joseph P. Landy, each a United States citizen and a Managing General Partner of WP and Managing Member and Co-Chief Executive Officer of WP LLC.

Each of Messrs. Kaye and Landy, together with the WP X Funds, WP Co-Invest, WP X LP, WP X GP, WPP GP, WP Partners, WP Partners GP, WP and WP LLC are collectively referred to herein as the “Warburg Pincus Reporting Persons.”

The principal business address of each of the Warburg Pincus Reporting Persons is 450 Lexington Avenue, New York, New York 10017.

See Item 2(a).

Common Stock, par value $0.0001 per share (the “Common Stock”).

29272B105

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The information required by Items 4(a)-(c) is set forth in Rows 5-11 of the cover page hereto for each Warburg Pincus Reporting Person and is incorporated herein by reference for each such Warburg Pincus Reporting Person.

Pursuant to a Stockholders Agreement (the “Stockholders Agreement”), dated October 24, 2013, by and among (i) the Issuer, (ii) the WP X Funds and WP Co-Invest (collectively, the “Warburg Pincus Investors”), (iii) GS Capital Partners VI Fund, L.P., GS Capital Partners VI Offshore Fund, L.P., GS Capital Partners VI Parallel, L.P., GS Capital Partners VI GmbH & Co. KG, Bridge Street 2011, L.P., Bridge Street 2011 Offshore L.P., and MBD 2011 Holdings, L.P. (collectively, the “Goldman Sachs Investors”) and (iv) certain other holders of Common Stock of the Issuer (together with the Goldman Sachs Investors, the “Other Investors”), each of the Warburg Pincus Investors and the Other Investors has agreed to vote the shares of Common Stock of the Issuer that each holds of record in a certain manner on matters related to the election of certain directors appointed by the Warburg Pincus Investors and the Goldman Sachs Investors. In addition, pursuant to the Stockholders Agreement, the WP X Funds and the Goldman Sachs Investors have certain rights to restrict the transfer of each other’s shares of Common Stock of the Issuer. The Warburg Pincus Investors and the Goldman Sachs Investors hold an aggregate total of 75,067,771 shares of Common Stock of the Issuer (approximately 56.7% of the outstanding shares of Common Stock of the Issuer), including 18,301,729 shares of Common Stock of the Issuer that are publicly reported as being owned by the Goldman Sachs Investors. The Warburg Pincus Reporting Persons are not entitled to any rights as a shareholder of the Issuer with respect to the shares of Common Stock of the Issuer beneficially owned by the Other Investors except as expressly set forth in the Stockholders Agreement. Each Warburg Pincus Reporting Person expressly disclaims beneficial ownership (within the meaning of Rule 13d-3 of the Exchange Act) with respect to any shares of Common Stock of the Issuer other than the shares of Common Stock of the Issuer owned of record by such Warburg Pincus Reporting Person. The number of shares of Common Stock of the Issuer owned by each Warburg Pincus Reporting Person as set forth in Rows 5 – 11 of their respective cover pages to this Schedule 13G/A does not reflect the aggregate shares of Common Stock of the Issuer owned by the Other Investors.

The aggregate total of 18,301,729 shares of Common Stock of the Issuer indicated in this Schedule 13G/A as being beneficially owned by the Goldman Sachs Investors is derived from the Goldman Sachs Investors’ Forms 4, filed with the U.S. Securities and Exchange Commission (the “Commission”) on December 1, 2014, and is not purported to be an accurate representation of the Goldman Sachs Investors’ beneficial ownership as of the date of this Schedule 13G/A. The Goldman Sachs Investors are responsible for reporting their beneficial ownership of shares of Common Stock of the Issuer on their own behalf, and the Warburg Pincus Reporting Persons disclaim responsibility for reporting the shares of Common Stock of the Issuer beneficially owned by the Goldman Sachs Investors.

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The percentages used herein are calculated based upon the 132,420,036 shares of Common Stock of the Issuer outstanding, representing 129,420,036 shares of Common Stock outstanding as of October 31, 2014, as stated in the Issuer’s final prospectus filed with the Commission pursuant to Rule 424(b)(4) of the Securities Act of 1933, as amended (the “Securities Act”) on November 21, 2014, plus 3,000,000 shares of Common Stock sold by the Issuer on November 26, 2014.

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following   ¨.

Other than as set forth herein, no other person has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, in excess of 5% of the total outstanding Common Stock.

Not applicable.

(1) The Warburg Pincus Reporting Persons are making this single, joint filing because they may be deemed to constitute a “group” within the meaning of the Exchange Act. The joint filing agreement among the Warburg Pincus Reporting Persons to file this Schedule 13G/A jointly in accordance with Rule 13d-1(k) of the Exchange Act is attached hereto as Exhibit 99.1.

(2) Each Warburg Pincus Reporting Person expressly disclaims beneficial ownership with respect to any shares of Common Stock of the Issuer other than the shares of Common Stock of the issuer owned of record by such Warburg Pincus Reporting Person.

Not Applicable.

Not Applicable.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: February 9, 2015

EXHIBIT 99.1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of the foregoing Statement on Schedule 13G/A with respect to the common shares of Endurance International Group Holdings, Inc. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that it knows or has reason to believe that such information is inaccurate. This Agreement may be executed in any number of counterparts and all such counterparts taken together shall constitute one and the same instrument.

Dated: February 9, 2015