With the worldwide growth of non-governmental organizations (NGOs) and other forms of transnational social activism, increasing numbers of international relations scholars are exploring what the phenomenon means for world politics. While there have been numerous studies on how transnational networks spur policy changes at international and national levels of politics, few of them explore the question of what these changes mean for regions and regional governance. My proposed research takes up precisely this question. I explore the role that NGOs and regional transnational networks are playing today in transforming emerging structures of regional governance, focusing in particular on East Asia, which I define to include both Northeast Asia and Southeast Asia. The project has three major goals. First, I seek to take the measure of transnational networks that are operating today in East Asia, looking at the forces that have triggered their emergence, and at the role of established advanced industrial democracies in the region, notably the United States and Japan, in fostering and shaping their growth. Second, I explore the role of transborder activism in regional governance, focusing in particular on four activities central to regional governance: efforts to (1) increase popular participation, (2) improve transparency and accountability, (3) provide services and (4) promote international cooperation. Finally, I shall assess the effectiveness of transborder networks in shaping policy outcomes in the region and the ways they are contributing to regional governance. To pursue these research questions, I shall examine regional networks active in the area of sustainable development and environmental protection. In this issue area, I will focus on two arenas of regional governance: the Asian Development Bank (ADB) and sub-regional conservation “eco-zones.” In four case studies I will investigate the networks that have emerged in these arenas, the types of governance functions that the networks provide and their effectiveness in bringing about policy change. The four cases focus on the role of transborder networks in: • Asian Development Bank (ADB) policymaking • ADB project implementation • the Sulu-Sulawesi Marine Ecoregion (the coastal waters of the Philippines, Indonesia and Malaysia) • the Greater Mekong System Biodiversity Conservation Corridor Initiative Field research for these cases will involve overseas travel to Japan, the Philippines, Thailand, Indonesia, and Malaysia. Data collection will include interviews, NGO publications and documents, government and ADB publications and documents, and other case-related books and publications. Although the study seeks to shed light on processes of governance in East Asia, it will also have wider relevance for work in the field of international relations concerning the role of nonstate actors in international politics and foreign policy. In addition to contributing to theory building regarding the multiple functions of NGOs in international cooperation, the study will also reveal the complex and varied relations between state and society in the creation and evolution of international institutions.