The main question in this research project is whether regional integration promotes the rule of law in ASEAN. The thesis has adopted a functional, rather than conceptual, approach to understanding the rule of law and its development in regional integration. While the approach reflects an instrumentalist function of the rule of law, the study provides a holistic and interdisciplinary approach taking account of the legal, insitutional, and political processes in the state, the region, and international relations to show the motivations and interests of member states in adopting a peculiar type of regional arrangement. The research project has taken the European Union for comparison, not as a model in the strict sense, to identify the development of legal and institutional processes that build the foundation of the rule of law and the factors that drive the evolution of state-like constitutionalism. Common legal tradition of the rule of law, leadership role of key member states, and regional institution building ??? are the main processes in the development of the rule of law in the EU and are either lacking, different, or weak in the context of ASEAN. However, an evolving form of the rule of law exists in ASEAN. The rule of law in ASEAN integration is designed to provide a stable and coherent framework for interstate relations among member states and to achieve effective implementation of the member states??? economic commitments. ASEAN has adopted an instrumentalist conception of the rule of law and one based on ???thin??? constitutionalism, as reflected in the ASEAN Charter. The features of the rule of law in ASEAN are ??? state-controlled, limited, evolutionary and resting on soft legal regime. ASEAN has chosen a different path at regional integration and globalization has offered new techniques of the rule of law. Regionalism in ASEAN remains statist in character and the ASEAN Way is still entrenched. There are significant developments towards adopting a broader basis of regional cooperation and opportunities for developing the rule of law in ASEAN. To broaden the function of the rule of law in regional integration, as a mechanism of accountability and as a form or restraint, ASEAN needs to adopt initiatives aimed at expanding political participation and respect for human rights. The European Union offer points of learning for ASEAN in achieving a broader function for the rule of law in ASEAN integration.