<p>Sustainable biocomposites, comprising natural fibers (NFs), biofillers, and biodegradable polymer matrices, are gaining traction as eco-friendly alternatives to synthetic composites. This review critically assesses recent progress in material development, surface modifications, and fabrication methods aimed at enhancing mechanical performance, biodegradability, and environmental compatibility. The synthesis presented aims to accelerate the shift away from petroleum-based systems and contributes to the global pursuit of the United Nations Sustainable Development Goals. Special focus is placed on out-of-autoclave (OoA) processing, which offers scalable, low-emission, and energy-efficient manufacturing routes aligned with circular economy principles. Comparative analysis of OoA techniques highlights their benefits in process simplification, reduced energy demands, and lower volatile emissions. However, challenges such as moisture absorption and weak fiber–matrix interfaces persist, limiting broader adoption. The review identifies these technical gaps and emphasizes the integration of life cycle assessment, biodegradability metrics, and multi-criteria decision-making frameworks like the analytical hierarchy process to inform sustainable material and process choices. Future directions are explored, including intelligent biocomposites design, renewable energy integration in curing processes, end-of-life management through recycling innovations, and addressing scalability challenges in additive manufacturing. This review provides a cohesive framework combining materials science, green manufacturing, and environmental evaluation, offering strategic guidance for advancing biocomposites.</p>