Used Cooking Oil (UCO) has become a key component in the transition to renewable energy, with rising demand in biodiesel and sustainable aviation fuel production. Once treated as waste, UCO is now seen as a valuable feedstock within the circular economy. However, the international policy landscape surrounding UCO remains fragmented, inconsistent, and vulnerable to misuse. This chapter explores the complex policy environment governing UCO across global, regional, and private-sector frameworks. It examines how international treaties address UCO either as a pollutant, a renewable energy source, or a tradable commodity. It also reviews national and regional policies such as the EU’s Renewable Energy Directive (RED), the United States’ Renewable Fuel Standard (RFS), and Low Carbon Fuel Standard (LCFS), and emerging strategies in Asia-Pacific countries like China, Indonesia, and Japan. Key challenges in UCO policy implementation include fraud in global trade, weak traceability systems, and uneven regulatory enforcement. The chapter discusses technological and policy innovations aimed at resolving these issues, such as blockchain, ISCC certification, and price benchmarking. It also highlights best practices in community engagement and private-sector governance that support sustainable UCO markets. In conclusion, the chapter argues for stronger international coordination, better regulatory alignment, and targeted incentives to ensure UCO can deliver on its environmental and economic potential. Balancing trade, sustainability, and social equity will be critical in shaping the future of UCO within global energy and waste management systems.