One of the most challenging obstacles to commercialization of perovskite solar cells (PSCs) is their instability toward environmental conditions. An emerging solution to overcome these challenges relies on graphene-based composites, in particular, solution-processable reduced graphene oxide (rGO), whose high electrical and thermal conductivity, along with beneficial passivation effects, display multifaceted utility in PSCs. This review provides a brief summary of functions of rGO in different PSC architectures, from a potential replacement for transparent conductive oxides, through usage in electron-transporting and perovskite layers, with the particular emphasis on its application as a hole-transporting material and a spacer layer. Despite ongoing research challenges, the synergy between rGO and PSCs promises to facilitate the future applications of efficient and stable PSCs.