Pluronic P-65 was appropriated as a structure-directing agent in this study to create mesoporous Mn3O4–ZnO nanostructured materials with 1, 2, 3, and 4 wt% Mn3O4 NPs. ZnO NPs (nanoparticles) were extremely disseminated and they were completely consistent in size or shape, with mean particle diameter close to 20 nm. The resulting mesoporous structure revealed by the produced Mn3O4–ZnO nanostructured materials had a large surface area as well as a large pore volume. Upon visible illumination, photocatalytic effectiveness of the manufactured Mn3O4–ZnO nanostructured materials was examined for tetracycline (TC) degradation and was furtherly correlated with those of pure ZnO NPs and commercial P-25. After 120 min of illumination by visible light, Mn3O4–ZnO heterojunction with 3.0 wt% Mn3O4 NPs was capable of accomplishing almost complete decomposition of TC however, only 3.7 and 8.9% of TC were decomposed by the application of ZnO NPs and commercial P-25 (commercial titanium dioxide), correspondingly. In other words, the removal effectiveness of such heterojunctions was 27 and 11-fold stronger than those of pure ZnO NPs and P-25, accordingly. In addition, the decomposition performance of 3 wt% Mn3O4–ZnO nanostructured material is eminent in comparison to other manufactured nanostructured heterojunctions. To investigate the mechanism of TC photocatalytic degradation, transient photocurrent intensity as well as photoluminescence characteristics were addressed. It is envisioned that this research may give some ideas for comprehending more heterojunctions with distinguished behaviorism.