This article studies English school’s position in International Relations’ (IR) theories. The main goal of the article is to answer to this question: “Is the English School a paradigm shift in IR”? Answering this question, the author discusses about the history of English School in IR in four main periods. Then the main elements and nature and branches of English School have been studied. Through that the two approaches of solidarism and pluralism and their differences and similarities have been mentioned. Also the most important methodological aspect of English school has been discussed through explaining the differences among international society, international system and global society.  The author places the English school of International relations via media between realism and idealism. To prove that theme, he explains the relations of the main factors of that School which are anarchy, order, balance of power etc with the mainstream’s concepts. Finally the author concludes that English School is a historical institutional approach in International relations which originated from realism and at last adjust some concepts of the mainstream and places between classical realism and classical liberalism. Because the English School does not have different ontological, epistemological and methodological concepts, we cannot recognize it as a paradigm shift in International Relations discipline.