the Good Friday Agreement in 1998, appeared to have put an end to the political violence between Catholics and Protestants in Northern Ireland. However, although violence has been reduced after the Good Friday Agreement, the conflict between the two groups, which has deep historical roots, is more likely to be considered a continuous problem on the island. In the Brexit climate where the contested rhetoric of 'sovereignty' is salient, the integrationist process of the GFA may reverse into re-segregation and ancient enmities between denominational groups. Therefore, using both psychological and historical analyses, this article discusses how Brexit affects national identity dynamics in post-conflict Northern Ireland from a political psychological perspective. [ABSTRACT FROM AUTHOR]