Recognizing the hydrogen economy to address the environmental and energy problems of the world may depend critically on the development of sustainable hydrogen generating techniques. Due to its environmentally friendly and affordable benefits, photocatalytic water splitting is preferred and emerging technique. To obtain the desired photocatalytic results, active, reliable, and affordable photo-/catalysts must be developed. In this scenario, co-catalysts provide a satisfactory solution to significantly improve photocatalytic performance. This review highlights current developments in co-catalyst research and development that have a substantial bearing on the catalytic activity and selectivity of photocatalytic hydrogen evolution reaction (HER). It offers in-depth knowledge on the production of co-catalysts for HER and acts as a broad roadmap to speed up the creation of extremely effective HER photocatalysts. Various factors affecting the performance of co-catalysts for HER were also discussed in details. Moreover, the logical design and synthesis of novel materials for extremely effective photocatalysis are made possible by this review. © 2024 Elsevier B.V.