The structural and optical properties of pure and Gd doped ZnO thin films have been investigated by XRD and UV-Vis spectrophotometer. Gadolinium doped Zinc oxide thin films with different percentage of Gd have been prepared by the spray pyrolysis method. The prepared samples were characterized by X-ray diffraction (XRD). The optical properties were studied by UV- Visible spectroscopy technique. The influence of Gd dopant on structural and optical properties of the prepared thin films were investigated and discussed based on the structure modification and band gap of undoped and Gd doped ZnO thin films.