Despite our many differences, one superordinate category we all belong to is ‘humans’. To strip away or overlook others’ humanity, then, is to mark them as ‘other’ and, typically, ‘less than’. We review growing evidence revealing how and why we subtly disregard the humanity of those around us. We then highlight new research suggesting that we continue to blatantly dehumanize certain groups, overtly likening them to animals, with important implications for intergroup hostility. We discuss advances in understanding the experience of being dehumanized and novel interventions to mitigate dehumanization, address the conceptual boundaries of dehumanization, and consider recent accounts challenging the importance of dehumanization and its role in intergroup violence. Finally, we present an agenda of outstanding questions to propel dehumanization research forward.