Zinc oxide thin films were deposited on glass substrate at a substrate temperature of 673K by spray pyrolysis method using different concentration of 0.0125M, 0.025M and 0.05M of Zinc acetate solutions. The effect of molar concentrations on structure, surface morphology and magnetic properties of ZnO films were investigated using x-ray diffraction, scanning electron microscopy and vibrating sample magnetometer. All deposited films were polycrystalline in nature with hexagonal wurtzite structure having a preferential growth orientation along (101) plane. An improvement of crystallinity in the deposits with increasing concentration of sprayed solution was noticed. All deposit exhibit fibrous structure which increases with increase of precursor concentration solutions. At room temperature, all deposited films were shown diamagnetic character but when cooled to 5K, they have shown paramagnetic characteristics.