This paper argues that the process of deriving legitimacy criteria for political institutions ought to be sensitive to features of the political context in which that process is to occur. The paper builds on Allen Buchanan’s ‘Metacoordination View’ of legitimacy, which we explicate in the first section. While sympathetic to Buchanan’s practical approach, we believe the idea of a metacoordination process to be underspecified across two dimensions, which we explain in the second section: (i) constituency and (ii) normativity. Both dimensions admit of differing specifications. In the third section, we suggest that how best to fill in these dimensions in any one instance depends upon the political context in which the metacoordination process is to occur. We highlight three relevant elements of a political decision context – criticality, institutional time point, and motivational landscape – and illustrate their significance by way of reference, respectively, to the World Health Organization, the European Economic and Monetary Union, and the Bank of International Settlements. The ‘context-dependence’ of the metacoordination process, and therefore of legitimacy, entails the possibility that institutions that are similar, even identical, in terms of their nature and function may nevertheless be held to differing legitimacy criteria in differing political contexts.