In this study, aluminum doped zinc oxide thin films were deposited on ordinary glass substrates at the temperature of 425 degrees C by spray pyrolysis technique for various doping concentrations of aluminum ranging from 1 to 5 at.%. The effect of dopant concentration on structural, morphological and optical properties of ZnO:Al thin films was studied. Optical band gap of the films increased with doping percentage and started to decrease from 2 at.% of dopant. The average transmittance for 2at.% ZnO: Al film is significantly increased over 90% in the visible region at 450 nm which is crucial for optoelectronic applications.