On 23 June 2016, 52 of Britons voted in a referendum to exit (Brexit) the European Union (EU), while 48% opted to remain. This major event in world politics has implications not only for the future of the UK, but for the future of regional and world orders as well. UK is one of the largest members of the EU, a leading member of NATO and a central player in transatlantic relations. As a European state, Britain has long drawn on the position of its continent in world affairs. By exiting the EU, UK had undermined the European pillar on which rests a great deal of British power, including influence in Washington. Brexit was the result of several interrelated factors, but most importantly the increased EU supranationality; the very feature that gave the EU its unique model. This supranationality was perceived by Eurosceptics within Britain as an erosion of British sovereignty. In general, the forces of globalization and regionalization have generated possibilities as well as a growing discontent inside the EU. Britain’s decision to question its membership of the EU is being perceived as a negative blow for regionalism. This paper argues that the growing importance of regionalism, not just in Europe, representing a variety of models and approaches, refutes the argument claiming that Brexit would mark the end of regionalism. The future of regionalism after Brexit will depend on multiple actors and cross-cutting drivers, emanating from the rise of a multiplex world order. Arguing that Brexit marks the end of regionalism loses sight of other actors, instruments, and modalities of regional orders. It also ignores the changing nature of the international system, in which the U.S. is no longer a hegemon with the capacity to shape regional orders. The paper employs several analytical concepts such as hegemonic regionalism, new regionalism and open regionalism. The paper looks at the Brexit vote and the future of regionalism within the theoretical framework of a post-hegemonic regionalized world order, in which the nature and purpose of regionalism and regional orders have changed and broadened. The paper also addresses the attempt of European countries to restore national autonomy in an attempt to stem migration and stop terrorism. This shift indicates a reprioritization of stability and security consideration over region-building.