[en] In this paper, we investigate the features of the Fourier-IR reflection spectra of γ-irradiated GaS crystals in the region of absorbed doses of Φ_γ = 30-200 krad at room temperature. Dispersion dependences of the real ε₁(ν) = n²-k² and imaginary ε₂(ν=2nk of the parts of the dielectric constant, the function Ιmε^-1(ν)=ε₂/(ε₁²+ε₂²), as well as the absorption n(ν) and refraction k(ν) coefficients for the initial and γ irradiated GaS samples were obtained and studied.The effect of γ quanta on the optical parameters of these crystals was considered. It has been established that at relatively low doses of 30 ≤Φ_γ≥100 krad are not radiation-resistant.