ZnO:Ga thin films were deposited on corning glass by dc magnetron sputtering. Influence of Ga-doped concentrations on the structural and optical properties of ZnO:Ga thin films were investigated. The XRD patterns show that the crystallinity of deposited films improved with the increase of Ga concentrations from 1 to 2%, then decrease at 3% Ga concentrations. The optical transmittance of films with 1% and 2% Ga concentration reach 85% in the visible range, while at 3% Ga concentration the transmittance of film only 70%. We observed that the band gap of film change due to the addition of Ga dopant. The band gap of the films are 3.27, 3.28 and 3.21 eV for 1, 2 and 3% Ga-doped concentrations, respectively.