Graphene oxide (GO) has emerged as a versatile two‑dimensional platform owing to its high surface area, tunable electronic structure, and abundant oxygenated functional groups, which collectively enable rich surface chemistry and colloidal stability in aqueous media. Decorating GO with inorganic and organic nanoparticles (NPs) provides powerful means to overcome intrinsic limitations of both partners, including GO’s moderate conductivity and the agglomeration, photocorrosion, or poor dispersion of bare nanoparticles. Over the last few years, rapid progress has been made in synthetic strategies for covalent and non‑covalent NP functionalization of GO, including hydrothermal, solvothermal, co‑precipitation, and bioinspired green methods, as well as in situ growth approaches that allow fine control over interface architecture. These advances have translated into markedly enhanced performance in photocatalysis, energy storage, sensing, and biomedicine, where NP–GO hybrids display improved charge separation, mechanical robustness, and multifunctionality compared with their single‑component counterparts. This review critically surveys recent literature on nanoparticle–GO hybrid systems, with an emphasis on structure–property relationships, mechanistic understanding of interfacial charge and mass transport, and application‑oriented performance. Particular attention is paid to green and bioinspired synthesis routes, the use of heteroatom doping and co‑doping, and the rational design of hierarchical architectures. Current challenges in reproducibility, scalability, toxicity, and long‑term stability are discussed in detail, and key knowledge gaps are identified. Finally, future research directions are proposed, including machine‑learning‑assisted materials discovery, standardized characterization protocols, and life‑cycle assessment of NP–GO nanohybrids for sustainable deployment.

Keywords: Graphene Oxide (GO); GO Synthesis Methods; Functionalization;