The aim of this article is to analyse the ontological and epistemological dimensions of the main stages of the development of regional studies as a sub-discipline of international relations. The research problem of the article focuses on the interdependence and significance of regional studies as a sub-discipline within the scholarly discipline of international relations. The issue of regionalism and the region arose in the period of the establishment of international relations as a scholarly discipline during the interwar years, and was further conceptualized in the 1950s and 1960s during the Cold War period. The status of regional studies was then marginalized in methodological, ontological and epistemological discourse by the main theoretical trends of international relations. As a result, it was only after the end of the Cold War that we witnessed a gradual, systemic process of reintegration of regional studies within the discipline. This article argues that the reintegration of regional studies into the discipline of international relations is a function of two parallel processes that are interrelated: the transformation of the liberal international order after the end of the Cold War and increased pluralism in scholarly discourse within the discipline of international relations. These developments and their associated academic implications have contributed to the consolidation and strengthening of regional studies as a major subdiscipline of international relations.