Zayo 10-Q 2016 Q2 Quarterly report

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Zayo Group Holdings, Inc. (the “Company”) on Form 10-Q for the three months ended December 31, 2015 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Dan Caruso, Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. §1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that:

(1) The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: February 12, 2016	By:	/s/ Dan Caruso
		Dan Caruso
		Chief Executive Officer