To date, extensively high demand for hydrogen peroxide (H 2 O 2 ) has been predominantly supplied by the anthraquinone process for several worldwide applications, encompassing wastewater treatment, environmental remediation, and chemical synthesis. However, the compacted manufacturing, massive energy input and the release of tremendous wastes have restricted commercialization feasibility. Regards to mitigate such issues, the photocatalytic H 2 O 2 production by utilizing g-C 3 N 4 catalysts has endowed a greener, sustainable and promising alternative, considering that it involves water and oxygen as reactants in the present of sunlight as energy input. Herein, we have manifested a comprehensive overview of the research progress for g-C 3 N 4 -based semiconductors for photocatalytic H 2 O 2 generation. This review has systematically elucidated state-of-the-art development of different modifications on g-C 3 N 4 to unravel the fundamental mechanism of H 2 O 2 evolution via oxygen reduction reaction (ORR) and water oxidation reaction (WOR). In addition, the contribution made by vacancy introduction, doping, heterogenization, and co-catalyst passivation with respect to photoefficiency enhancement have been clarified. Furthermore, the current challenges and perspective of future development directions on photocatalytic H 2 O 2 production have also been highlighted. As such, g-C 3 N 4 stands as the next step toward advancement in the configuration and modulation of high-efficiency photocatalysts.