This chapter explores the evolving role of startups in advancing the circular economy (CE) across key Asian countries: South Korea, Japan, China, and India. Against a backdrop of rapid population growth, industrialization, and increasing waste, CE principles—reduce, reuse, and recycle—offer a compelling framework for sustainable development. While governments have begun to implement supportive CE policies, progress remains slow, often hindered by limited commitment and policy inertia. Startups, in contrast, are demonstrating agility and innovation in recycling, re-manufacturing, and sustainable packaging, while navigating diverse regulatory and cultural landscapes. Drawing on case studies, this chapter shows that startups are not only enablers of CE practices but also critical intermediaries between policy and behavior. However, their success depends on a supportive ecosystem, including public awareness, government incentives, and technological infrastructure. The findings underscore that CE adoption in Asia is contingent on collaborative networks—between governments setting strategic direction, startups driving implementation, and citizens participating in circular practices. Ultimately, regional CE progress will require knowledge exchange, coordinated efforts, and scalable solutions rooted in local contexts. This chapter highlights the potential of startups to transform sustainability ambitions into practical and community-centered outcomes.