Multipolarity has ambiguous implications for the legitimacy of global governance institutions (GGIs). Rising powers’ capacity to contest established powers’ agendas prima facie increases the GGIs’ legitimacy by reducing power asymmetries between the North and South. However, according to some, the rise of new powers has contributed to the GGIs’ poor performance and inadequate representativeness. We investigate how global publics evaluate the legitimacy of two GGIs—the World Trade Organization (WTO) and the Group of Twenty (G20)—and multipolarity’s role in those evaluations. Drawing on an original dataset of 3,584 newspaper articles sampled from rising and established powers, mid-ranking developing, and least developed countries between 2008 and 2019, our qualitative content analysis found an intensification of legitimacy deficits over time. Regularly accredited to a new global power configuration, the inability to find consensus severely harmed both institutions’ legitimacy. We also see the resilience of GGIs’ legitimacy in the face of gridlocks and institutional fragmentation. Replacing inclusive multilateral agreements with bilateral or inter-regional ones was widely seen as an undesired outcome of major power tensions. Finally, our data revealed a deep-seated mistrust of great power politics and nostalgia for meaningful multilateral institutions as a potential antidote.