AbstractElectron shuttles are pivotal in enhancing the conversion efficiency at the biotic‐abiotic interface within microbial photoelectrochemical systems. Nevertheless, the potentially toxic effects of electron shuttles on microbial cells and their instability when exposed to light are often overlooked. This concept highlights the attention paid to electron shuttles in microbial photoelectrochemical systems, such as the cytotoxicity, the photoexcited state, and the photostability. Furthermore, it offers theoretical guidance for selecting electron shuttles to optimize sustainable energy production and environmental remediation.