Abstract In the past decades, great efforts have been made to develop efficient solar-to-fuel conversion devices using III–V semiconductors. In this chapter, a brief history of III–V photoelectrodes for photochemistry and their synthesis methods are firstly reviewed. Then, an important category of solar-energy-conversion devices, photoelectrochemical solar cells, constructed by III–V photoelectrodes in contact with redox couples is discussed. The discussion also includes up-to-date basic understanding of the interfacial photoelectrochemistry between semiconductors, redox, and catalysts with liquid electrolytes. Finally, fuel-forming photoelectrodes for hydrogen evolution, water oxidation, overall water splitting, and CO 2 reduction are summarized, with emphasis on the recently developed protective coating strategies.