In the current study, a comparison between the different 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 confirmed by the XRD and SEM analysis. The nanocrystalline ZnO, M₃O₄, CuO and Fe₂O₃ phases were observed with different 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 different 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 efficiency 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 purification compared to the other nanocomposites.