The densely functionalized graphene oxide (GO) surface and the two-dimensional carbon structure had provided a unique opportunity for supporting photocatalysts. Concerning GO-based photocatalysis, GO plays the role of an electron acceptor that accelerates the interfacial electron-transfer process, recombination retardant of charge carriers, finetuner for the electronic and chemical properties of the supported photocatalysts, and finally, a carrier transport between different active sites. Moreover, standalone GO is a p-doped semiconductor material with the π* orbital of the oxygen remains as the conduction band minimum (CBM) while the valance band maximum (VBM) changes gradually from the p-orbital of carbon to the 2p orbital of oxygen upon oxidation. The outstanding features of the GO-based photocatalysis opened the way to serve the progress in many environmental applications including water treatment, air purification, water splitting, CO 2 conversion, and sensing applications.