Reduced graphene oxide (rGO) has tunable properties and acts as an efficient low-cost alternative for graphene in many applications. It also has its own exciting electronic and optoelectronic characteristics. The properties of rGO can be altered by tuning the amount of reduction, types of defects, doping and functionalization. The reduction of graphene oxide (GO) by various methods and the large-scale production of rGO can be easily achieved. These properties led the research drive for low-cost and high-end applications of rGO-based devices. It has found applications in almost all branches of applied science and engineering. Recent research works show that rGO-based photodetectors achieved high responsivity and detectivity values with fast operation speed. Although there are many reviews on graphene-based photodetectors, there has been much less focus on rGO-based photodetectors. In this review, we focus on rGO-based photodetectors, photodetection mechanism and advancements in the field. Thus, in this review, we provide a much-needed timely update and future prospects to the scientific community. © The Royal Society of Chemistry 2021.