In this article I argue that the very meaning of ‘inter-national relations’ is emerging as a focus of debate in International Relations, particularly among the critical traditions in the discipline. No longer seen as a mere study of peace and war, IR is viewed as a component of general pan-disciplinary theories or order and change. The international sphere is perceived, accordingly, no longer as a system in its own right, but rather as a gigantic transmission belt, and a huge communication device transmitting and diffusing ideas, practices, rules, norms and institutions throughout the world. The article examines the implications of such an approach on IR theory. In addition, the article revisits the works of Hegel, Marx and the French School of Regulation to demonstrate how they developed an empirical theory of international diffusion.