Photocatalytic hydrogen evolution can effectively alleviate the troublesome global energy crisis by converting solar energy into the chemical energy of hydrogen. In order to realize efficient hydrogen generation, a variety of semiconductor materials have been extensively investigated, including TiO2, CdS, g‐C3N4, metal‐organic frameworks (MOFs), and others. In recent years, to achieve higher photocatalytic performance and reach the level of large‐scale industrial applications, photocatalysts decorated with transition metal phosphides (TMPs) have shone brightly because of their low cost, stable physical and chemical properties, and substitution for precious metals of TMPs. This Review highlights the preparation methods and properties associated with photocatalysis of TMPs. Moreover, the H2 generation efficiency of photocatalysts loaded with TMPs and the roles of TMPs in catalytic systems are also studied systematically. Apart from being co‐catalysts, several TMPs can also serve as host catalysts to boost the activity of photocatalytic composites. Finally, the development prospects and challenges of TMPs are put forward, which is valuable for future researchers to expand the application of TMPs in photocatalytic directions and to develop more active photocatalytic systems. H2 evolution: This Review highlights the preparation methods and properties of transition metal phosphides (TMPs). Moreover, the hydrogen evolution efficiency of photocatalysts loaded with TMPs and the roles of TMPs in catalytic systems are also studied systematically. In addition, several TMPs can also serve as host catalysts to boost the activity of photocatalytic composites. This work demonstrates the importance of TMPs in the photocatalytic conversion of solar energy into chemical energy.