The article is devoted to the problem of understanding the role of colonial policy in the English School of International Relations. The evolution of the concept of international society in the 1980s makes it possible to identify the line between colonial and postcolonial discourse in the texts of representatives of this scientific community. The paper analyzes both the positions of individual scientists on colonial subjects and the collective practice of the English school, presented in the monograph “The Expansion of International Society” (1984). In the course of the study can be distinguished two different positions of scientists in relation to colonialism. The original participants of the English School formulated the first. It proceeded from the need to take colonial history beyond the concept of international society. The origins of the formation of such an attitude can be explained both by the peculiarities of the personal destinies of scientists (C. Manning) and by the specifics of their scientific views (M. Wight, M. Howard, A. Watson). The second position presented by a new generation of supporters of the English school. It assumed a rethinking of the role of colonialism in history in the context of the formation of the modern global world. R.J. Vincent in his work of on Japan's entry into the international system had beginning of such a rethinking. Using this example, the scientist showed the need to study the reverse impact of colonies on the norms and institutions of European international society. H. Bull supported his student, despite the fact that R.J. Vincent's position contradicted the general theory of the development of international society. As a result, the school started talking about the works of the late H. Bull. Thus, he softened the criticism of the new participants. The further development of the concept led to the position that modern supporters of the English School consider colonialism to be an institution in the history of the formation of international society. Moreover, the participation of former colonies is recognize as a fundamental moment of the modern structure of international society. H. Bull, one of his late publications, tried to combine these approaches and identified new prospects for the development of the concept of the English School of International Relations.