Photocatalytic reactions mediated by metal halide perovskites (MHPs) have become a topic of current interest because of the promise of improved low-cost devices for solar fuel production. Thanks to their excellent optoelectronic properties, namely tunable band gap, high absorption coefficient, low exciton binding energy, and high carrier mobility, MHPs were successfully applied to a wide range of photocatalytic reactions. Furthermore, a suitable band alignment of MHPs with the most common redox half-reactions allows to run both reduction and oxidation reactions, as confirmed by the recent experimental demonstrations of the two most representative examples, namely hydrogen photogeneration and CO2 reduction. With respect to traditional metal oxides photocatalysts, MHPs present a large chemical and structural variety, which allows the design and tailoring the material composition for the envisaged solar-drive reaction. In this respect, both lead-based and lead-free systems have been explored, ranging from 3D to 2D perovskites, perovskite derivatives of general formula A3B2X9, and A2(BB′)X6 double perovskites. The general strategy to realize a spatial separation of photo-excited electron-hole pairs in MHPs-based photocatalysts is to design suitable heterojunctions by coupling two semiconductors. In addition, the second semiconductor can also act as co-catalyst to improve surface reaction. Again, the high tunability of MHPs allows the design of materials with suitable conduction band (CB) and valence band (VB) offsets to achieve the heterojunction and to provide enough overpotential to drive the target photoreaction.