Zirconium dioxide thin films were prepared by e-beam evaporation method to study the effect of substrate temperature on the structural, surface morphology, compositional, and optical properties. X-ray diffraction measurement shows that the films grown at 400 â„ƒ substrate temperature have monoclinic crystal structure. The root mean square surface roughness of the film increases with increase in the substrate temperature. The optical transmittance spectra indicate an average 80% transmittance in the visible region of light. The optical energy band gap of ZrO2 thin film decreases from 5.68 to 5.63 eV as the substrate temperature increases from room temperature to 400 â„ƒ, respectively.