We have synthesized Ga 1− x Mn x As 1− y P y and Ga 1− x Mn x P 1− y N y by the combination of ion implantation and pulsed-laser melting. We find that the incorporation of isovalent impurities with smaller atomic radii leads to a realignment of the magnetic easy axis in Ga 1− x Mn x P 1− y N y /GaP and Ga 1− x Mn x As 1− y P y /GaAs thin films from in-plane to out-of-plane. This tensile-strain-induced magnetic anisotropy is reminiscent of that observed in Ga 1− x Mn x As grown on larger lattice constant (In, Ga)As buffer layers indicating that the role of strain in determining magnetic anisotropy is fundamental to III–Mn–V materials. In addition, we observe a decrease in the ferromagnetic Curie temperature in Ga 1− x Mn x As 1− y P y with increasing y from 0 to 0.028. Such a decrease may result from localization of holes as the P/As ratio on the Group V sublattice increases.