It is often said that the institutions of criminal justice ought or—perhaps more often—ought not to rehabilitate criminal offenders. But the term ‘criminal rehabilitation’ is often used without being explicitly defined, and in ways that are consistent with widely divergent conceptions. In this paper, we present a taxonomy that distinguishes, and explains the relationships between, different conceptions of criminal rehabilitation. Our taxonomy distinguishes conceptions of criminal rehabilitation on the basis of (i) the aims or ends of the putatively rehabilitative measure, (...) and (ii) the means that may be used to achieve the intended end. We also explore some of the implications of each conception, some of the payoffs of a taxonomy of the kind we offer, and some areas for future work. (shrink)