Exhibit 24
                               POWER OF ATTORNEY
                                October 13, 2014

      The undersigned hereby constitutes and appoints each of Scott E. Beer and
Ken desGarennes, the General Counsel & Secretary and Chief Financial Officer,
respectively, of Zayo Group Holdings, Inc. (the "Company"), signing singly and
not jointly, with full power of substitution, as the undersigned's true and
lawful attorney-in-fact to:

(1)   prepare, execute in the undersigned's name and on the undersigned's
      behalf, and submit to the U.S. Securities and Exchange Commission (the
      "SEC") a Form ID, including amendments thereto (the "Form ID"), and any
      other documents necessary or appropriate to obtain codes and passwords
      enabling the undersigned to make electronic filings with the SEC of
      reports required by the Securities Exchange Act of 1934, as amended (the
      "Exchange Act"), or any rule or regulation of the SEC;

(2)   prepare, execute in the undersigned's name and on the undersigned's
      behalf, and submit to the SEC, any and all Forms 3, 4, and 5 (the "Section
      16 Filings"), including amendments thereto, required to be filed under
      Section 16(a) of the Exchange Act and the rules thereunder with respect to
      equity securities of the Company;

(3)   do and perform any and all acts for and on behalf of the undersigned which
      may be necessary or desirable to complete and execute such Form ID and any
      Section 16 Filings and to file such Form ID and any Section 16 Filings
      with the SEC and any stock exchange or similar authority; and

(4)   take any other action of any type whatsoever in connection with the
      foregoing which, in the opinion of such attorney-in-fact, may be of
      benefit to, in the best interest of, or legally required by, the
      undersigned, it being understood that the documents executed by such
      attorney-in-fact on behalf of the undersigned pursuant to this Power of
      Attorney shall be in such form and shall contain such terms and conditions
      as such attorney-in-fact may approve in such attorney-in-fact's
      discretion.

      The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite,
necessary, or proper to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as the undersigned might or
could do if personally present, with full power of substitution or revocation,
hereby ratifying and confirming that each such attorney-in-fact, or such
attorney-in- fact's substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and powers herein
granted.  The undersigned hereby authorizes, approves, and ratifies any and all
prior actions taken by such attorneys-in-fact in connection with the matters
contemplated herein.  The undersigned acknowledges that such attorneys-in-fact,
in serving in such capacity at the request of the undersigned, do not assume any
of the undersigned's responsibilities to comply with the Exchange Act or any
rule or regulation of the SEC.

      This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file a Form ID, any Section 16 Filings, or
any amendments or changes thereto, with respect to the undersigned's holdings of
and transactions in securities issued by the Company, unless earlier revoked by
the undersigned in a signed writing delivered to the foregoing attorneys-in-
fact.


      IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of the date first written above.



                                          By: /s/ Daniel P. Caruso
                                              ------------------------------
                                          Name: Daniel P. Caruso