The glass-forming region in the GeS2–Ga2S3–PbI2 system was determined and the basic parameters of thermal and optical properties (glass transition temperature, density, microhardness and transmission window) for these glasses have been measured. Better thermal stability originated from their larger difference between Tx and Tg in the range of 107–161 °C, higher glass transition temperatures between 252 and 398 °C and wide optical transmission window from 0.5 to 12.7 μm make these glasses the promising candidate materials for rare earth doped fiber amplifiers and nonlinear optical devices.