This study investigated national identity and intergroup attitudes and howstrength of national identity impacts on in-group and out-group attitudes. Thedata were gathered in post-violence Northern Ireland with children aged 7 and11 years of age. A total of 148 children took part (Catholic participants: n ¼ 73and Protestant participants: n ¼ 75). Eight schools were selected, 4 Protestantschools and 4 Catholic schools. Children were individually interviewed in theschool setting. A significant positive correlation between strength of nationalidentity and affect towards the in-group was found for Protestant participants.A significant negative correlation between strength of national identity andaffect towards the traditional enemy was found for Catholic participants. Therewas also evidence of in-group bias, in that both Protestant and Catholicchildren evaluated their own group more positively than the other out-groups.In addition, it was found that younger children are more sensitive to negativecomments about their own national identity than older children. These findingsare discussed in terms of previous findings and theoretical perspectives.