Graphene oxide has aroused significant interest for a range of applications owing to their outstanding physico-chemical properties. Specifically, the presence of a large number of reactive chemical moieties such as hydroxyl, carboxyl, epoxide, and sp2 carbon allows these novel materials to be tailored with additional functionalities with the purpose of tuning intrinsic properties. There has been a vivid discussion on the non-covalent modification of GO; however, a comprehensive summary of the chemical functionalization which enables forming a stable particle is still elusive. Hence, in this study, we summarize recently advanced methodologies used for designing the functional GO for their use in specific applications. Together with a brief discussion on the essential characterization techniques, this study will provide fundamental insight into the latest developments in the preparation of covalently modified GO derivatives, thereby leading to their broader utilization in future.