The influence of the sequence of doping with CuCl and Ga during thermal doping of ZnS on the luminescence characteristics of a prepared luminophore was studied. The diffusion processes of Ga and CuCl in ZnS were analyzed, as well as the role of these impurities in the formation of light-emitting centers in ZnS:(CuCl, Ga). It was shown that the sequence of doping allows variation in the color coordinates (X = 0.242−0.351, Y = 0.555−0.551) of the ZnS:(CuCl, Ga) luminophore and the intensity of the emission band at 404 nm.