BiVO4 thin films doped with various concentrations of sulfur were fabricated using RF sputtering followed by post-deposition sulfurization. The incorporation of sulfur in the samples was calculated to be approximately 8–11 at.% from the S2s peak in their X-ray photoelectron spectra. The optical bandgap of sulfur-doped BiVO4 was generally smaller than that of the undoped sample. BiVO4 films doped with ~ 8 at.% sulfur showed the highest photoelectrochemical performance compared to the undoped sample, plausibly due to the decrease in the bandgap, facilitating more photoexcited carriers to contribute to the photoelectrochemical reaction. A further increase in sulfur doping above 8 at.% distorted the BiVO4 local crystal structure, inducing defects, thus resulting in a lower photocurrent.