In this paper I aim to answer the question of who made the United States Constitution as law. On the account I offer to be a maker of a constitution as law is to satisfy two conditions: (1) to act intending to make a constitution and viewing oneself as having authority to do so and (2) to be de facto authoritative in making a constitution. Beginning with a sketch of the historical process of the making of the Constitution, I then identify the agents involved in it. I observe that on any plausible account the making was a cooperative process involving groups of people and thus I consider the issue of group agency, arguing that groups can act and have intentions when certain conditions are satisfied. Several candidates for the Constitution’s maker are evaluated in this paper: ‘We the People’, ‘the Drafters’, ‘the Ratifiers’, ‘the Great Men’, the states and the peoples of the states. The historical material available does not allow for a decisive answer to the question who was the maker. However, I conclude that based on the available evidence it is most compelling to view the thirteen state groups of the Ratifiers as the makers of the Constitution, because they viewed themselves as acting to establish the Constitution with authority delegated by the people of their states and because their act of ratification was, in fact, recognized as establishing the Constitution as law. Other candidates likely did not satisfy the first condition of being the maker.