Uranium (U) resources play a crucial role in energy utilization; however, uranium contamination in wastewater and soil has caused severe damage to the ecosystem and human health. Addressing this challenge requires the development of cost-effective and environmentally sustainable remediation materials. This review highlights the environmental merits of biochar-based materials in uranium decontamination, focusing on the diverse applications of modification techniques for enhancing the properties of pristine biochar. By analyzing over 110 relevant studies, the review demonstrates that biochar derived from various biomass sources, with proper modification, could exhibit high adsorption capacities for immobilising uranium in aqueous and soil environments. The primary removal mechanisms identified include physical adsorption and chemical reduction. These works indicate that biochar, produced from green feedstocks and featuring superior reusability, represents a cost-effective, sustainable solution for uranium remediation. Moreover, its application aligns with carbon sequestration and waste valorization, supporting sustainable development goals. Looking ahead, the engineering performance-oriented biochar materials with tailored physicochemical properties hold significant promise for addressing uranium contamination challenges. This review provides a comprehensive evaluation of biochar-based materials as a green alternative for uranium remediation and offers valuable insights into advanced material modification strategies to enhance reactivity and effectiveness.