This Introduction to the Symposium on Constituent Power reflects on the changes subsequent to the transfer of fundamental constitutional norms from domestic to global contexts. This transfer raises the issue of legitimate global order. Is it possible to address this issue of legitimacy of global governance by shifting the conceptual focus from debates about global constitutionalization towards the involved multiple actorship as a potential constituent power? Is asking a question about the pouvoir constituant helpful in analyzing global constitutionalism as a remedy for the shortcomings of global governance? All contributions to this symposium elaborate on the insight that the concept of constituent power offers a crucial conceptual tool for mapping “unbound” constitutional quality. The developing process of global constitutionalization appears to go hand in hand with a contestation of the very norms promoted by global constitutionalism. This observation raises some general issues about the ultimate effectiveness of global constitutionalization which this symposium attempts to cope with.