This essay discusses how the recent rise of populist leaders worldwide influences the institutional dynamics of the liberal international order (LIO). Drawing on Hedley Bull‘s five institutions of modern international society, the study explores populists‘ delegitimation of the LIO and the resulting systemic impact. This exercise underscores the increasing erosion of the international institutions that characterise the post-Cold War LIO due to populists projecting discursive antagonism between people and elites onto the international sphere by promoting personalistic diplomacy, highly politicised ad-hoc transnational networks, and incendiary attacks against „foreign“ elites. In parallel, populists undermine the LIO when reluctant to balance revisionist attitudes, defend fundamental liberal rights, and manage new crises. Thus, populists are leading the way to an international order more prone to instability, polarisation, and radicalisation. The study aims to contribute to the growing scholarly efforts to analyse multiple contestations of the liberal script(s) in the current inter- national order.