Drawing on the anti-positivist philosophy of science of Roy Bhaskar, ‘critical realism’1 has sought to challenge some of the core assumptions theorists hold on the nature of explanation and science in IR theoretical inquiry.2 One important area in which critical realists challenge disciplinary conventions in IR is the issue of causal analysis. Causation has been a contested notion in much of twentieth-century philosophy of science and social science and, since the late 1980s, has also been debated in International Relations, where the causal approach of the positivists has come under increasing criticism from a selection of post-positivist ‘constitutive’ theorists. Critical realism seeks to reformulate currently dominant understandings of the role and nature of causal analysis in the social sciences and in IR. This short contribution to the forum focuses on examining the critical realist intervention to the debates on causal analysis in IR. Critical realism, it is argued, opens up important new avenues in IR theorists’ and researchers’ conceptions of causal analysis: avenues previously hidden from view by the dominance of a positivist view of science in IR.