Gallium-doped zinc oxide (ZnO:Ga) films are prepared on glass substrates by rf magnetron sputtering at room temperature. The structural, electrical and optical properties of the ZnO:Ga films with various thickness are studied in detail. The crystal structure of the ZnO:Ga films is hexagonal wurtzite. The orientation for all the obtained films is along the c-axis perpendicular to the substrate. It is observed that with an increase in film thickness, the crystallite sizes of the films are increased. The lowest electrical resistivity among the films is found to be about 3.1 x 10(-4) &UOmega; cm and the average transmittance for all films including substrates is over 83% in the visible range. © 2004 Elsevier B.V. All rights reserved.