The effect of rare earth (Dy and Sm) and transition metal (Mn) luminescent impurities on the optical properties of As₂S₃ glass is studied in a wide spectral region. The Raman, infrared, band-to-band and edge absorption spectroscopies are employed to obtain information about the incorporation of impurity ions in the host glass structure and the corresponding changes in intrinsic optical characteristics. The effects of light-soaking and thermal treatment on the doped As₂S₃ glasses were examined as well. In the fundamental absorption region a reflectivity maximum at 2.98 eV shows blue (Dy, Sm) or red (Mn) shift depending on the electronegativity of the impurity, in accordance with the corresponding variations of the glass structure. Near the edge absorption the impurity affects strongly the slope and the magnitude of the weak absorption tail. In the wide range of transparency the addition of impurity suppresses several absorption bands indicating the interaction of dopants with the host glass contaminations. Some variations of the characteristic Raman spectra under light exposure and thermal ageing of doped glasses were registered. The observed effects of metal dopants on the As₂S₃ glass are discussed in connection with the expected behaviour of the impurities in the glass.