High transmittance Ga-doped ZnO thin films were deposited on glass substrates using sol-gel spin coating technique. Crystallinity levels, microstructures, optical and electrical properties of the thin films were systematically investigated by scanning electron microscope, X-ray diffractometer, UV-visible spectrophotometer, PL spectrometer and four-point probe method, respectively. All GZO thin films exhibited polycrystalline with a hexagonal wurtzite structure and slight (0 0 2) preferred orientation growth, which show excellent transmittance (>95%) in the 380-780 nm wavelength range. The PL spectra of the GZO films revealed a strong ultraviolet emission peaks at around 393 nm and a weak blue emission peak at around 468 nm. When the Ga doping level was 4 at.%, the minimum resistivity of 1.12 x 10(-2) Omega.cm with the highest transmittance was reached. The optical band gaps (E-g) of the films were increased from 3.311 eV to 3.329 eV with the increase of Ga dopant concentration. (C) 2016 Elsevier B.V. All rights reserved.