In this article, I discuss a distinctively nonparadigmatic instance of punishment: the punishment of noncitizens. I shall argue that the punishment of noncitizens presents considerable difficulties for one currently popular account of criminal punishment: Antony Duff’s communicative expressive theory of punishment. Duff presents his theory explicitly as an account of the punishment of citizens – and as I shall argue, this is not merely an incidental feature of his account. However, it is plausible that a general account of the criminal law of the kind of idealized state that Duff focusses on will need to say something about how that law deals with noncitizens. In particular, I claim, it will need to provide a justification for punishing them. Because Duff's account says nothing about the punishment of noncitizens, it cannot do so. Furthermore, although Duff's more recent suggestion that noncitizens should be thought of as being guests in the state on whose territory they are present may provide for an account of their criminalization, it cannot easily be extended into an account that provides a justification for their punishment.