The growing interest in sustainable materials has led to a rise in demand for bionanocomposite materials, which integrate biodegradable polymers with nanoscale fillers. These composites offer innovative solutions for various applications but also pose significant questions regarding their environmental impacts throughout their life cycles. This chapter examines the life cycle assessment (LCA) of bionanocomposite materials, focusing on their ecological footprints throughout various stages of production, use, and disposal. The chapter begins by discussing the concept of bionanocomposites and the pressing need to evaluate their environmental impacts in the context of global sustainability challenges consistent with the UNDP sustainable development goals. The current methodologies for LCA are discussed taking into consideration resource extraction, application, and disposal with their associated water and energy consumptions. The challenges and opportunities in conducting comprehensive LCA for bionanocomposites are thoroughly discussed, and recommendations for achieving sustainability in bionanocomposites production and applications are recommended. Also, the comparative environmental benefits and drawbacks of bionanocomposites relative to conventional materials are examined. This chapter will serve as a valuable resource for researchers and practitioners of LCA and ESG professionals in understanding the potential of bionanocomposite materials in contributing to a more sustainable future. Ultimately, this chapter provides insights that can guide future research and policy initiatives aimed at promoting the adoption of environmentally friendly materials in diverse applications.