During the last decades ‘causation’ has been a deeply divisive concept in International Relations (IR) theory. While the positivist mainstream has extolled the virtues of causal analysis, many post-positivist theorists have rejected the aims and methods of causal explanation in favour of ‘constitutive’ theorising. It is argued here that the debates on causation in IR have been misleading in that they have been premised on, and have helped to reify, a rather narrow empiricist understanding of causal analysis. It is suggested that in order to move IR theorising forward we need to deepen and broaden our understandings of the concept of cause. Thereby, we can radically reinterpret the causal-constitutive theory divide in IR, as well as redirect the study of world politics towards more constructive multi-causal and complexity-sensitive analyses.