Guilt theoretically functions to motivate reparative behaviors, which, in turn, theoretically function to alleviate guilt and prevent psychopathology. Although several empirical studies in adults have demonstrated that guilt and reparative behaviors function as theorized, research has not investigated causal relations between guilt and reparative behaviors in children. Thus, this study examined whether guilt motivates children’s reparative behaviors, and whether their reparative behaviors successfully alleviate guilty feelings. Six-to ten-year olds (N = 97) were randomly assigned to one of three conditions. In the experimental condition, children were led to believe that they had transgressed to cause a peer’s distress. Children self-reported their guilt feelings following the pretend transgression, and then had the opportunity to repair the transgression by giving stickers and writing a note to the victimized peer. Following the repair opportunity, children self-reported their guilt a second time. Children in the experimental condition (i.e., children who felt guilty) engaged in greater reparative behavior relative to children in a no-guilt condition who were led to believe that they had caused a peer’s positive emotions. Further, children in the experimental condition reported reduced guilt at the second measurement, whereas children in the no-repair condition (who were led to believe that they had transgressed but were not be given a repair opportunity) did not report reduced guilt over time. Results demonstrate that guilt and reparative behaviors function as theorized in children and may begin to inform reparative interventions aimed at preventing unalleviated, maladaptive guilt and psychopathology.