The aim of the present study was to build on John Greer's systematic set of studies concerned with teenage beliefs and values conducted among samples of sixth form students attending County and Protestant voluntary schools in Northern Ireland in 1968, 1978 and 1988. The present study replicated the earlier surveys for a further time in 1998. The results provide a unique snapshot of the persistence of religious affiliation, belief and practice across the latter part of the twentieth century in a nation which has continued to resist the secularisation process so eroding the place of religion in the neighbouring nations of England, Wales and Scotland. (Contains 12 tables.)