Ten Southeastern Asian nations have formed an economic community. While the free movement rules are community-wide and the nations aspire to achieve a single market, there is no present plan for a community competition law. Can the nations achieve a single market without a common competition law? To answer the question, the paper examines, first, paradigmatic single-market competition rules and the work they do. Second, turning to the world, which has no international competition law: What problems are posed by the absence of an international framework and how well can they be solved in its absence? Third, it reflects on models other than community-wide competition law that share the space between tight integration of markets and loose coordination of nations and their competition authorities. Fourth, back to ASEAN, it identifies the particular problems posed by the absence of community competition law, and asks two questions: How much can the ASEAN nations solve with 10 national competition laws plus cooperation and coordination?, and: What principles and initiatives are most critical in helping ASEAN approximate a single market without community competition law?