The effect of deposition temperature on the surface morphology and optical properties of zinc oxide (ZnO) thin films were studied. The ZnO films were deposited on microscopic glass substrates using the spray pyrolysis method for different substrate deposition temperatures. The deposited films were characterized by an X-ray diffractometer (XRD), a spectrophotometer, scanning electron microscopy (SEM), and atomic force microscopy (AFM). The transmittance spectra recorded through the spectrophotometer exhibits 85% transmittance. The XRD spectra showed polycrystalline nature of ZnO film. Surface parameters were calculated and compared for different thin films. It showed that the films were polycrystalline with hexagonal wurtzite structure and c-axis was perpendicular to the substrate. The grain size of the films changed from 240 to 440 nm with different substrate temperatures. The optical energy gap of thin films increases from 3.26 eV to 3.35 as the substrate temperature increasing from 660 K to 700 K. It was found that growth temperature has significantly affected the morphological (grain size, surface roughness) as well as optical properties of ZnO films, which are extremely important as they can improve or degrade the device performance.