Although North American integration has been the topic of heated public debate, it has not yet received adequate theoretical attention from the field of international relations. This article reviews the movement to codify North American integration, and explores the implications for integration and international relations theory. The first section reviews the intellectual history of integration theory as it developed in the European context. The second considers the North American experience of codifying integration, 1982–1994. The third part returns to integration theory and international relations, offering some amendments and suggestions considering the North American experience. The article argues that the clearest understanding of regional integration in the 1990s can be achieved through an approach which stresses developments in the global political economy as catalysts for change, and looks to national and transnational institutions and social forces to explain variations in integration projects. Because other international relations theories such as neofunctionalism and interstate bargaining are unable to integrate these levels of analysis, they offer an incomplete view of present dynamics.