This article introduces the concept of hegemonic constituent power to argue for a greater role for the people in the process of Irish reunification through the establishment of a constituent assembly. Hegemonic constituent power contends that, ideally, constituent power should be possessed by the people; however, descriptively, this is invariably not the case. Constituent power instead is best understood as the manifestation of hegemony – the dominant power base in a given legal order that legitimates and reinforces this power through institutions, prevailing ideas and culture. Hegemony performs an important function in descriptively explaining legitimacy formation while not necessarily conferring normative legitimacy on existing power structures or those who exercise constituent power. Legitimacy and illegitimacy are both embedded in this notion of hegemonic constituent power. This allows for constituent power to perform a legitimating function and its creative potential to be unleashed while still leaving space for critical contestation over how this power was exercised. In this way, hegemonic constituent power also seeks to address critiques of constituent power as enabling populism. The article then deploys this concept of hegemonic constituent power to argue that fears of invoking the will of the people in debates on Irish reunification are misplaced.