Middle childhood seems to be crucial for the emergence of a moral identity, that is, an evaluative stance of how important it is for someone's sense of self to be moral. This study investigates the effects of moral identity on the neural processing of moral content in 10-year-old children. Participants were presented with scenes portraying prosocial and antisocial behavior, while electroencephalographic responses were collected. Analyses of event-related potentials (ERPs) showed that, for children with a strong moral identity, antisocial scenes elicited a greater early posterior negativity (EPN) as compared to prosocial scenes. Thus, for children with a strong moral identity, antisocial scenes capture more attentional resources than prosocial ones in early processing stages. In contrast to previous findings with adults, the implicit moral self-concept was not related to any ERP differences. Overall, the results show that, even in its developmental emergence, moral identity relates to the neurocognitive processing of third-party moral content. Together, the study supports the social-cognitive model of the development of moral identity, according to which moral identity is based on a chronical activation of moral schemas that guide a person's perception of the social world.