By causing a serious gap in the optimistic literature on European integration processes, Brexit has provided numerous challenges for international relations theorists. In this regard, in the present article, three influential theories that best explain Brexit will be discussed: neorealism, constructivism, and the English school of international relations. Notwithstanding that both neorealism and constructivism are able to raise important issues, it seems that there are still certain shortcomings in the two theories in explaining Brexit. Neorealism relies too much on macro-analysis and material factors, and, on the other hand, constructivism tries to account for essential factors from the domestic or secondlevel analysis. Therefore, the paper's central question is how does the English School provide a convincing explanatory framework for understanding Brexit? In response to the question, the paper adopts a theoretical perspective to analyze and explain both the micro-level and macro-level of the Brexit phenomenon by utilizing the English School’s central assumptions: institutions, the great power status, pluralist-solidarist debate, and the balance of power. It is concluded that English School is able to explain Brexit more satisfactorily. According to the school’s assumptions, Brexit is not an oddity, but a natural consequence of internal and external equations in the United Kingdom.
