This study examined the role of aggressiveness and parenting in the development of children's moral self-concept. Participants were 198 elementary school children and their parents (M = 8.65 years, SD = 2.44). Participants completed a structured moral self puppet interview and a questionnaire about their relationship to parents. Parents completed a questionnaire measuring their children's aggressiveness. Results indicated that children who were more aggressive scored significantly lower on the moral self than did less aggressive children. Positive parent-child relationships predicted higher scores on children's moral selves. Finally, negative parent-child interaction moderated the effect of aggression, with negative associations between aggression and children's moral self exacerbated at high levels of negative parent-child interaction, and attenuated at lower levels. This study elucidates the importance of aggression and parenting in accounting for differences in children's moral self.