Abstract We report the effect of Ni-doped ZnO thin films on the photodegradation of methylene blue (MB) under visible irradiation. The Ni-doped ZnO thin films were deposited on a silicon substrate by ultrasonic spray pyrolysis (USP) at 450 °C for 15 minutes. The ZnO thin films are characterized by X-ray diffraction (XRD) and UV-Vis spectroscopy. The X-ray diffraction (XRD) pattern for all samples confirms that the crystalline phase of Ni-doped ZnO thin films is polycrystalline hexagonal wurtzite. However, due to the Ni incorporation into the ZnO site, there is a change in the crystal plane. All ZnO films confirmed photocatalytic properties, indicating methylene blue (MB) degradation under visible irradiation. Nevertheless, the degradation of the MB dye increased by about 76% with increasing Ni incorporation. Therefore, we confirmed that Ni incorporation affects the photocatalytic properties of the ZnO thin films.