The growth of circular nanotechnology provides disruptive solutions for sustainable resource management, waste valorization, and low-impact production. However, robust international cooperation is necessary to expand these technologies efficiently and fairly across areas. This chapter examines cross-border research projects, multi-stakeholder platforms, and multinational collaborations that are speeding up the creation, standardization, and use of circular nanotechnologies. It shows effective examples of government, business, and academic cooperation that support innovative ecosystems and facilitate technology transfer, particularly to poor and emerging nations. Joint ventures in zero-waste manufacturing, nano-enabled clean energy, and nanomaterial recycling are given particular attention. Critical enablers include mechanisms like harmonized regulatory standards, collaborative financing structures, and open-access databases. Additionally, the chapter looks at the function of international organizations, public-private partnerships, and cooperative networks, including Horizon Europe, the UN’s Technology Facilitation Mechanism, and Mission Innovation. Asymmetries in research capability, geopolitical difficulties, and intellectual property issues are among the obstacles to collaboration that are critically examined. This chapter seeks to encourage inclusive and scalable global action to incorporate circular nanotechnology into sustainable development objectives by outlining workable routes and policy proposals.