This chapter sheds light on the multinational research project approach to global governance, which is known as global administrative law (GAL), with a focus on the unease GAL has expressed with its own constitutional implications. The argument proceeds as follows. First, it is explained why GAL’s approach to global governance echoes the history of responding to the emergence of modern administrative agencies with administrative law in the United States. It is also noted that GAL reframes the world of national legal orders as a ‘global administrative space’. Second, it is shown that GAL turns to the idea of ‘publicness’ to address the dual challenge of legality and legitimacy and the question of legal pluralism arising from the heterogeneity of global governance. Finally, the chapter concludes with a discussion of the unsettled relationship between GAL and global constitutionalism.