The United States has developed its Indo-Pacific strategy since 2017, when Donald Trump visited Asia and advocated for the importance of the region. Despite initial ambiguities, the United States has begun to sharpen its strategic vision in managing its rivalry with China. One of the most important strategic foci is institution-building, namely the Quad—the grouping of Australia, India, Japan, and the United States—as illustrated by the Biden administration's initiative to hold the Quad Summit in March 2021. However, the Quad poses a strategic problem for the Association of Southeast Asian Nations (ASEAN), which has been pivotal in managing Asian regional multilateralism and mitigating great power rivalry. ASEAN responded by producing the ‘ASEAN Outlook on the Indo-Pacific’ and emphasizing ‘ASEAN Centrality’ to lead Indo-Pacific regionalism, aiming to mitigate US–China competition. Although the United States expresses strong support for ASEAN's initiatives, the Quad has become institutionally more prominent in ways that could marginalize ASEAN. This chapter analyzes the future of institutional arrangements in the Indo-Pacific region, and how institutional competition between the Quad and ASEAN-led institutions can be avoided.