In the current study, a comparison between the diferent Mn3O4/ZnO, CuO/ZnO and Fe2O3/ZnO nanocomposites with respect to their structural, morphological, optical and photocatalytic properties is presented. The nanostructure nature of the investigated composites was confrmed by the XRD and SEM analysis. The nanocrystalline ZnO, M3O4, CuO and Fe2O3 phases were observed with diferent crystalline structure, including hexagonal, tetragonal, monoclinic and rhombohedral, respectively. The morphology of ZnO based nanocomposites was found to be dependent on the type of the metal oxide added to ZnO nanostructure. In addition, the studied nanocomposites showed diferent optical properties. The highest and lowest band gap of 3.14 and 2.00 eV were obtained for ZnO nanoparticles and Fe2O3/ZnO nanocomposite. Concerning the photocatalytic properties, the ZnO nanoparticles, Mn3O4/ZnO, CuO/ZnO and Fe2O3/ZnO nanocomposites showed an efciency of 49.63, 29.8, 11.61 and 95.34%, respectively, for the photodegradation of methylene blue. The Fe2O3/ZnO nanocomposites exhibited the highest activity for water purifcation compared to the other nanocomposites