GaTe thin films were deposited by thermal evaporation technique. The effect of annealing on the structure and optical properties was studied. X-ray diffraction of the as deposited films indicated that the films have a polycrystalline nature. Annealing at 473 K for 2 hours enhanced the crystallization and changed the preferential orientation from (
21) plane for as deposited films to (110) plane for annealed films. Study of the optical band gap showed that; these films have direct band gap of 1.53 eV. Annealing increased the band gap to 1.62 eV. The effect of annealing on the optical parameters such as refractive index, extinction coefficient, dispersion energy parameters, and dielectric constants were investigated.