There is growing public awareness in the United States of state-sponsored programs of non-consensual sterilization (NCS), particularly of poor, nonwhite, and cognitively disabled people. Although many today regard the practice as morally unjustified, there has been little discussion in bioethics of why exactly it is wrong. I aim to correct this glaring oversight. I argue that NCS is wrong because it is dehumanizing—tantamount to treating a person as other than, or less than, human. Specifically, victims of NCS are treated as nonhuman animals, which profoundly shapes the practice’s moral topography. My view has two primary virtues. First, it implies that whether NCS is permissible or wrong does not depend on whether the victims want or intend to procreate, whether procreation contributes to their well-being, or whether they experience suffering in the wake of the deprivation. Second, my view explains why NCS is often experienced by its victims not just as wrongful but also as deeply degrading, and it predicts—correctly—that the stigma of NCS is particularly acute for people independently subjected to animalizing stereotypes, such as nonwhite and cognitively disabled people. I consider and reject alternative explanations of the wrong of NCS, such as that it violates victims’ (procreative) autonomy, amounts to treating them merely as a means, or imposes bodily/psychological harms on them. My discussion suggests that the critical vocabulary of bioethics should be expanded beyond talk of rights-violations, benefits and harms, and equal treatment—and that a nuanced language of dehumanization is indispensable to bioethicists.