The parental caregiving motivational system leads people to behave selflessly. However, given that the purpose of this motivation is the protection of close kin, it might also lead to aggression toward distant, threatening others. In the present studies, we wished to investigate the effects of behaviorally activating the caregiving motivational system on out-group bias. On the basis of previous work in behavioral ecology, we predicted that activation of the caregiving system would enhance bias against out-groups whenever their members posed a salient threat. This prediction was confirmed in three studies (total N = 866) across different populations, manipulations, and measures. We discuss the possible importance of continued research into the behavioral consequences of caregiving salience.