Graphene oxide (GO) has emerged as a promising nanomaterial with physicochemical properties that make it a candidate for a wide range of applications. However, the potential toxicity of GO is a significant threat that must be addressed before GO’s safe use in biomedical and environmental applications can fully be realized. Numerous studies have demonstrated that GO has the ability to induce oxidative stress, inflammation, genotoxicity, and cytotoxicity in cell types and animal models. Importantly, the toxicity of GO is influenced by its size, morphology, charge, and surface functional groups. The current review summarizes recent research findings on the toxicity of GO by focusing on its cellular uptake, biodistribution, and biological effects. It provides an overview of the current understanding of GO nanotoxicity and highlights the need for additional research to assess its safety in various applications. By addressing these concerns and developing appropriate safety measures, we can fully exploit the potential of GO while ensuring its safe utilization in biomedical and environmental settings. Thus, the comprehensive evaluation of GO’s potential risks is crucial for its full exploitation and utilization.