The transition toward a sustainable and circular bioeconomy demands innovative strategies that simultaneously address global energy needs and waste management challenges. Nanotechnology has emerged as a transformative enabler, offering unprecedented opportunities to enhance bioenergy production while valorizing diverse waste streams. This chapter explores the integration of nanomaterials and nanotechnological interventions within the circular bioeconomy framework, focusing on their role in converting biomass and organic residues into clean, renewable energy. Particular emphasis is placed on engineered nanomaterials that significantly improve the efficiency of biofuel, biogas, and hydrogen production pathways. In parallel, the application of bioinspired nanostructures, nanozymes, and quantum dots for waste valorization are examined, highlighting their potential in recycling agro-waste and industrial by-products into value-added products. The chapter also evaluates environmental, economic, and policy dimensions, with particular attention to life cycle assessment, safety considerations, and alignment with the United Nations Sustainable Development Goals (SDGs). By bridging nanotechnology with circular bioeconomy principles, this work underscores the potential of nano-enabled innovations to accelerate the transition toward carbon-neutral energy systems and sustainable resource recovery. Ultimately, this chapter provides a roadmap for researchers, policymakers, and industry stakeholders to harness nanotechnology in creating resilient, circular, and sustainable bioenergy ecosystems.