The visible luminescence from Pr³⁺, Dy³⁺, Nd ³⁺, Sm³⁺ and co-doped with Ho³⁺ and Dy ³⁺ ions embedded in Ga_0.017Ge_0.25As _0.083S_0.65 glass hosts at room temperature and at T=10 K is reported, when pumping with an Ar⁺-ion laser at λ=488 nm. Fluorescence emissions at 1.3 μm was observed for Dy³⁺ and both at 1.3 and at 1.5 μm for Pr³⁺ doped glasses with wavelength pumping at 950 nm. The emission bands correlate with the absorption bands characteristic for the electronic transitions of the rare-earth ions. Energy transfer from Ho³⁺:⁵F₃ level to Dy³⁺: ⁴F_9/2 level increase the visible emission efficiency at 650 nm in the co-doped glasses. The emission spectra correlate with the absorption spectra of the investigated glasses. The investigated Ga _0.017Ge_0.25As_0.083S_0.65 glasses doped with Pr³⁺ are promising materials for optical fibers amplifiers operating at 1300 and 1500 nm telecommunication windows. The effect of oxygen on the absorption and luminescence spectra of Pr³⁺-doped Ga-La-S-O (GLS) glasses with a constant cationic ratio Ga/La=0.7/0.3 and varying both oxygen (0.65 and 2.95 wt %) and praseodymium (0.1 and 1.0 wt %) content also are presented.