Recombination processes in GaNP(As) alloys were studied by an analysis of photoluminescence spectra in wide temperature and excitation power ranges. Temperature dependent photoluminescence studies shown carrier localization effects characteristic of Highly Mismatched Alloys group of semiconductors. Low temperature GaNP(As) emission was attributed to localized and delocalized exciton recombination by power dependent photoluminescence studies. Also, a non-monotonic dependence of the Stokes shift and emission intensity as a function of nitrogen content were found and attributed to a deactivation of localization centers due to the N content increase induced conduction band edge downward shift. Two activation energies were determined from photoluminescence thermal quenching analysis. In GaNP these energies were found to be approximately 13 meV and 50–35 meV, the second decreased with the increase in N concentration. For constant N content and varied As in the GaNPAs layers the two activation energies decreased between 13–8 meV and 50–30 meV, both with As increase.