We investigated when young children first dehumanize outgroups. Across two studies, 5‐ and 6‐year‐olds were asked to rate how human they thought a set of ambiguous doll‐human face morphs were. We manipulated whether these faces belonged to their gender in‐ or gender outgroup (Study 1) and to a geographically based in‐ or outgroup (Study 2). In both studies, the tendency to perceive outgroup faces as less human relative to ingroup faces increased with age. Explicit ingroup preference, in contrast, was present even in the youngest children and remained stable across age. These results demonstrate that children dehumanize outgroup members from relatively early in development and suggest that the tendency to do so may be partially distinguishable from intergroup preference. This research has important implications for our understanding of children's perception of humanness and the origins of intergroup bias. The developmental origins of dehumanization were investigated across two studies. We asked a sample of 5‐ and 6‐year‐olds to judge how human a set of ambiguous doll‐human face morphs were when they belonged to their ingroup and their outgroup. In Study 1, the groups were based on gender and in Study 2 they were based on geographical location. In both studies, older children showed a tendency to perceive less humanness in outgroup faces. Interestingly, the strength of this dehumanization bias did not relate to children's explicit intergroup preference.