Heterostructure semiconductors are considered as suitable candidates for solar-driven photo-electrochemical (PEC) water splitting due to their viable photoactive nature. Therefore, in this article, we have demonstrated the synthesis of Ga2O3/ZnO nanorods arrays (NRAs) by two-step physical vapor deposition (PVD) and wet chemistry method, directly on the glass and indium tin oxide (ITO) support. Morphological features, structural properties and chemical composition were investigated by scanning electron microscopy (FESEM), X-ray diffraction (XRD) spectroscopy and EDX, respectively. The optical properties through photoluminescence (PL) revealed that with increasing concentration of gallium content, reduction of visible peak of the PL spectrum is observed. Additionally, an ultra-thin nanofilm of gold nanoparticles (AuNPs) is also sputtered on the Ga2O3/ZnO NRAs to make Au/Ga2O3/ZnO heterostructures photoanodes. These photoanodes successfully split water under artificial solar light. Our results indicated the Au/Ga2O3/ZnO NRAs heterostructure photoanodes, which assimilates two different semiconductors with tunable band gaps can be realistically applied to photoelectrochemical applications.