Moral pride is a key component of virtue development. This study provides developmental insight into children's moral pride across cultures, and the potential for moral pride to underlie prosocial behavior. Participants included children and adolescents ages 6, 9, and 12 years from Canada (n = 186; 50% girls; ethnically diverse sample), Japan (n = 180; 48% girls), and a subsample from Italy (n = 86; 54% girls), as well as their primary caregivers or teachers. Moral pride was measured using a vignette procedure wherein children reported their emotions, emotion intensities, and reasoning following moral actions (harm omission and prosocial contexts). Global prosocial behavior was assessed via caregiver reports. Results revealed that moral pride increased from 6 to 9 years of age in Japanese and Canadian children (some similar trends were found in the Italian subsample) and that Canadian children reported stronger feelings of moral pride than Japanese children (Italian children's moral pride intensities were akin to those of Canadian children). Moral pride was positively associated with global prosocial behavior in Japanese children (and marginally in Italian children) but not in the Canadian children. These novel findings showcase the role of culture in shaping children's moral pride, and the potential for this moral emotion to reinforce children's commitment to prosocial action in childhood and early adolescence.