This article introduces International Political Ergonomics. International Political Ergonomics is a novel research programme focused on achieving political change through the ergonomic (re)design of world politics. The approach is grounded on a shift across International Relations which recognizes that its epistemic (i.e. knowledgeproducing) core is often inadequate to achieve change. Insights from the practice turn and behaviouralist International Relations, as well as from philosophy, sociology and neuroscience, demonstrate that much international behaviour is driven by the ‘unconscious’ or ‘non-reflexive’ re-articulation of repertoires of actions even where the pathologies of this process are known. This implies that knowledge production and dissemination (i.e. to policymakers, global publics) is often unable to effect influence over social practices. What is thus required is a non-epistemic means of producing world political change. International Political Ergonomics is a research programme that takes up this task. It does so by describing how small material interventions into world politics can radically shift individual behaviours by encouraging greater rationality, reflexivity and deliberation. After laying out the theoretical basis for this claim, the article demonstrates it by detailing the application of International Political Ergonomics to violence-prevention efforts. The article concludes by reflecting on the radical implications that International Political Ergonomics has for the vocation of International Relations.