A number of smart city projects claim to be ‘citizen-centric’, they aim to use technological innovation to foster citizen engagement and participation. However, it is unclear who is included and excluded from the concept of citizenship. A non-legal definition includes residents, commuters or tourists. However, the legal status of citizen is defined in relation to a state and a national government, not a local community. Interestingly, in Ancient Greece, citizenship was defined by reference to the city and shaped in terms of local participation. This paper explores the mismatch between the way citizen participation is framed legally and the way it is framed technologically in smart cities. It does so by drawing on the historical meaning of citizenship, exploring the goals of smart cities and citizen participation, and the problem of exclusionary effects stemming from technological biases, as well as the possibility of ‘opting out’ of the smart city.