Abstract: Zinc oxide (ZnO) thin films doped with molybdenum (Mo) have been grown on corning 7059 glass substrates by spray pyrolysis technique. The layers were deposited for different solution concentrations ranging from 0.01M to 0.2M, keeping Mo – doping constant as 2 at. %. The change in properties of the films by varying Zn molarity was studied. X-ray diffraction studies showed polycrystalline nature of the films with (002) preferred orientation and exhibited wurtzite structure. The layers formed at 0.1M molar concentration exhibited better crystallinity compared to other layers. Raman studies are in good agreement with XRD. Surface morphology varied significantly with Zn-molar concentration. An average transmittance of the layers was 80% in the visible region and the band gap varied from 3.31 eV to 3.5 eV. The detailed analysis of the results including photoluminescence are reported and discussed.