When collective decisions should be made democratically, which people form the relevant demos? Many theorists think this question is an embarrassment to democratic theory: (1) because any decision about who forms the demos must be made democratically by the right demos, which itself must be democratically constituted and so on ad infinitum; and (2) because neither the concept of democracy, nor (3) our reasons for caring about democracy, determine who should form the demos. Having distinguished between these three versions of the demos problem, we argue that each of them can be solved.