In this research work, we report the photocatalytic properties of ZnO synthesized in several forms: ZnO thin films deposited by atomic layer deposition (ALD), ZnO nanofibers synthesized by electrospinnig, and ZnO nanorods realized by chemical bath deposition onto ZnO thin films grown by ALD. The methylene blue was employed as a representative dye pollutant to evaluate the photocatalytic activity of the samples. All the nanostructured materials showed an enhancement of the photocatalytic activity with respect to the thin films. It was found that ZnO nanorods deposited onto 3 nm thin film showed the best photocatalytic activity. The relevance of the results is discussed, opening the route for the application of ZnO in photocatalysis.