A novel heterojunction photocatalyst of TiO₂–SrIn₂O₄ is found to be active for hydrogen generation from water as well as for the degradation of methylene blue under sunlight type radiation. Photocatalytic activity for hydrogen generation increases with increase in SrIn₂O₄ concentration and the optimum concentration is found to be 40% (by weight). The presence of a Pd co-catalyst enhances the photocatalytic activity and the catalyst is found to be stable after repeated cycles of photocatalysis experiments. A higher rate of degradation of methylene blue is observed when the composite is used as photocatalyst compared to pure TiO₂ and SrIn₂O₄. Detailed characterization of the composite revealed that TiO₂ exists as a dispersed phase on SrIn₂O₄ and the particle size of TiO₂ and TiO₂–SrIn₂O₄ is around 20 nm and 15 nm, respectively. Photocurrent experiments show a relatively higher current output for the composite compared to pure TiO₂. The enhanced photocatalytic activity of the composite is attributed to a synergistic effect of the increased lifetime of the charge carriers in the composite and increased surface area of the sample. The dispersion of TiO₂ nanoparticles on SrIn₂O₄ results in the formation of hetero-junctions between TiO₂ and SrIn₂O₄ leading to efficient interfacial transfer of photogenerated electrons from TiO₂ to SrIn₂O₄ and enhancing the lifetime of the charge carriers. The Pd co-catalyst enhances the activity of the composite further by increasing the availability of electrons in it and providing active sites for hydrogen evolution.