Regionalism has been one of the main topics of social science, comparative politics, international economy, international relations, and international political economy in the last two decades. There is no consensus about its meaning among scholars. It is often considered as integration in international politics. Perhaps one of its reasons is the more objectivity of it in the regional level. Sometimes regionalisms perceived as intergovernment, and increased cooperation of different states. The main question of this essay is “what are the causes of development of regionalism theory?”; the assumption of the authors is that intra and supra theoretical factors have lead to changes in these theories.