The present study examined whether bullying, defending, and outsider behaviors in preschool children were associated with two conscience aspects (empathic concern and internalization of rules) and with emotion understanding. We also investigated whether emotion understanding moderated the relationship between these dimensions and bullying roles. Participants were 105 children (51 males), aged 36 to 76 months. Bullying roles were assessed through peer nominations. Internalization of rules and empathic concern were observed in classroom and their scores derived from selected Q-Sort items. Emotion understanding was evaluated with the Puppet Interview administered to children. Results showed that empathic concern and internalization of rules were negatively associated with bullying and outsider behaviors, whereas emotion understanding correlated with defending behavior. The interaction between emotion understanding and internalization of rules was also significant: Low scores on rule-compatible conduct were associated with bullying or outsider behavior, in particular for those children with poor emotion understanding.