As the integrated education movement in Northern Ireland passes its twenty-first anniversary, it is pertinent to explore the legacy of mixed Catholic and Protestant schooling. This paper summarises the findings of different studies regarding the impact of integrated education in Northern Ireland on social identity, intergroup attitudes and forgiveness and reconciliation. The research is discussed in relation to its implications for the theory and practice of integrated education in Northern Ireland and also for other societies with a legacy of ethnopolitical conflict. It proposes that integrated education in Northern Ireland impacts positively on identity, outgroup attitudes, forgiveness and reconciliation, providing hope and encouragement for co-education strategies in other countries that have suffered from prolonged conflict. Despite a number of challenges, it is clear from the research presented here that integrated education holds great both for building social cohesion and for promoting forgiveness and reconciliation.