This study focuses on regions and approaches to regionalism in Europe, which has a long history and heritage. It was anticipated that the regions would be represented more strongly at the European level when the European Common Market was completed. Indeed, after joining the European Union, many European countries have guaranteed to govern their regions in accordance with the principles of subsidiarity and subordination. But some autonomous regions, such as Catalonia, emerged with "radical" demands such as independence rather than broad autonomy. The study tackled the issue from a current and historical point of view by carrying out some debates on the major regions of Europe. In the first part, regions that have evolved into separatism in Europe from time to time were discussed by focusing on the autonomous regions in Spain and the United Kingdom. In the second part, the regions in Italy were discussed, and the issues of identity, ethno-linguistic belonging, internal colonization and economic backwardness were elaborated. Finally, the establishment of the Committee of the Regions, a European Union institution, for the institutional solution of regional problems within the European Union and the criticisms faced by the Committee were evaluated. Thus, the way of ensuring the regional governance of the European Union institutions and their perspectives on regional differences were also revealed.