The results of spectral measurements and the differential thermal analysis (DTA) data for glasses in the Ga₂S₃-GeS₂-Nd₂S₃ system are presented. The boundaries of the glass formation region in the Ga₂S₃-GeS₂-Nd₂S₃ system are determined. It is shown that the luminescence efficiency increases with an increase in the gallium sulfide content due to the displacement of the concentration quenching boundary of Nd³⁺ luminescence with a change in the glass matrix composition.