EXHIBIT 4.1 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the reference to our firm under the caption "Experts-Independent Registered Public Accounting Firm" and to the use of our report dated March 27, 2013 in the Amendment No. 2 to the Registration Statement (File No. 333-186176) and related Prospectus of Guggenheim Defined Portfolios, Series 1015. /s/ Grant Thornton LLP ---------------------- GRANT THORNTON LLP Chicago, Illinois March 27, 2013