UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (date of earliest event reported): November 24, 2015

Tallgrass Energy GP, LP

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (913) 928-6060

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Item 1.01. Entry into a Material Definitive Agreement.

On November 24, 2015, Tallgrass Energy Partners, LP (“TEP”) and certain of its subsidiaries entered into Amendment No. 2 (the “Amendment”) to the Credit Agreement dated as of May 17, 2013 with Barclays Bank PLC, as administrative agent, and a syndicate of lenders (the “Credit Agreement”).

The Amendment modifies certain provisions of the Credit Agreement to, among other things, (i) increase the amount of the revolving credit facility to $1.1 billion and (ii) provide for a $400 million committed accordion feature (the “Committed Increase Commitments”).

TEP has a one-time option, exercisable on or prior to May 24, 2016, to exercise all or a portion of the Committed Increase Commitments if, among other things, TEP, on or before such date, acquires at least an additional 10% equity interest in Tallgrass Pony Express Pipeline, LLC, which owns and operates the Pony Express System, an approximately 764-mile crude oil pipeline commencing in Guernsey, Wyoming, and terminating in Cushing, Oklahoma.

The Committed Increase Commitments will be reduced on a dollar for dollar basis by the principal amount of any senior notes that are issued by TEP prior to the first to occur of the date TEP exercises its option for the Committed Increase Commitments and May 24, 2016.

Tallgrass Energy GP, LP (“TEGP”) is the managing member of and therefore controls Tallgrass Equity, LLC (“Tallgrass Equity”). Tallgrass Equity, in turn, controls TEP through the direct ownership of 100% of Tallgrass MLP GP, LLC (“TEP GP”), TEP’s general partner. As a result, under generally accepted accounting principles, TEGP consolidates Tallgrass Equity, TEP GP, TEP, and TEP’s subsidiaries. TEGP has no operations outside of its indirect ownership interests in TEP.

The foregoing description is not complete and is qualified in its entirety by reference to the full text of the Amendment, which is filed as Exhibit 10.1 to this Current Report on Form 8-K and incorporated into this Item 1.01 by reference.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The description of the Amendment provided above under Item 1.01 is incorporated into this Item 2.03 by reference.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

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 hereunto duly authorized.

INDEX TO EXHIBITS