Social identification processes can be seen as the basis of the conflict in Northern Ireland. During the conflict it can be argued that preferred social and political identities became increasingly oppositional and entrenched. This paper reviews this evidence using population level studies. It also explores trends in preferred identities since the 1998 Agreement as well as examining the patterns of preferred identity across generations with particular attention being paid to the responses of young people. In an attempt to elucidate the meaning of these identities, a series of inter-related qualitative studies that have examined constructions of national, political and religious identification are reported. These suggest a fluidity, rather than entrenchment, in post-Agreement respondents and point to the variability and complexity of identity phenomena in Northern Ireland.