Based on reflexive stocktaking and data collected from a cross-country survey distributed in seven Southeast Asian academic communities, namely Cambodia, Indonesia, Malaysia, Singapore, Thailand, the Philippines, and Vietnam, this article explores how much progress Southeast Asian international relations (IR) academic communities have made in advancing a theory or concept based on local experiences. It is argued that while mainstream IR remains dominant, debates since the early 2000s have introduced new concepts. At the same time, new theoretical proposals are rare due to the vast diversity in Southeast Asia and a general interest in producing policy- and empirical-oriented work. Nevertheless, there are opportunities for constructing a Southeast Asian theory based on the region’s distinct perspectives on international relations shaped by ASEAN norms and institutions and the complex interactions between politics at the domestic and international levels. Any new conceptual or theoretical framework must also provide useful implications beyond the region.