The photocatalytic performance of common photocatalysts is limited by their low surface area, insufficient absorption of light energy, and fast photogenerated electron-hole recombination rate. The introduction of Z-scheme photocatalysts decorated with hexagonal boron nitride (h-BN) has already been confirmed to be an effective way to extend the surface area and increase the charge separation, thereby enhancing the photocatalytic performance. In this study, a hexagonal boron nitride (h-BN)-decorated WO 3 /g-C 3 N 4 heterojunction photocatalyst was successfully synthesized via an in situ method using tungstic acid, melamine, and hexagonal boron nitride as the precursors. The physical and chemical properties of the resulting samples were thoroughly characterized. The surface, morphological, and optical properties of the resulting materials were thoroughly characterized by XRD, XPS, SEM, TEM, UV-vis DRS, BET surface areas, PL, and ESR analysis. The WO 3 /g-C 3 N 4 /BN composite exhibited a much higher photocatalytic activity for tetracycline degradation under visible light irradiation than pure g-C 3 N 4 , WO 3 , and BN. The favorable photocatalytic activity of WO 3 /g-C 3 N 4 /BN composites can be ascribed to the increased surface area and enhanced separation efficiency of photogenerated electron-hole pairs by adding h-BN nanosheets and forming the WO 3 /g-C 3 N 4 heterojunction. This work indicates that the WO 3 /g-C 3 N 4 /BN photocatalyst is a promising material in wastewater treatment.