This research investigates the varied approaches of teachers in Catholic primary schools of the Archdiocese of Armagh (Ireland), towards religious belief – their ‘belief styles’ – and explores how this might impact on religious school ethos in the changing socio-cultural context of Ireland today. It uses a quantitative approach in the form of a research instrument developed by the Enhancing Catholic School Identity project based at KU Leuven – the Post-Critical Belief Scale. This study reveals an overall picture of the primary school teachers sampled in the diocese who are engaged Christians with strong faith and an appreciation of diversity and plurality. Unsurprisingly however, given the socio-cultural context, a relativist approach to religious belief is evident among teachers and has the potential to become culturally dominant in Catholic schools into the future, possibly undermining their faith-based identity and ethos.