We study the regularity of solutions of elliptic fractional systems of order 2s, s is an element of (0, 1), where the right hand side f depends on a nonlocal gradient and has the same scaling properties as the nonlocal operator. Under some structural conditions on the system we prove interior Holder estimates in the spirit of [1]. Our results are stable ins allowing us to recover the classic results for elliptic systems due to S. Hildebrandt and K. Widman [11] and M. Wiegner [19]. (C) 2018 Elsevier Masson SAS. All rights reserved.