This research reports pupils' perceptions of their quality of school life in primary schools in Northern Ireland, investigated through development and use of a culturally adapted instrument with both experimental (Irish-medium) and control (English-medium) groups. A related issue examined via a second culturally adapted instrument was the pupils' attitudes towards the Irish language. Findings show that there is a significant difference in the perception/attitude profiles of both groups. However, the magnitude of the effects is small, with both sets of pupils being positively disposed overall towards their quality of school life. This is a noteworthy finding when the comparative under-resourcing of Irish-medium schools is taken into account. Findings also reveal that Irish-medium pupils have highly instrumental views of schooling. The research developed robust and culturally compatible instruments which offer a useful starting point for an examination of school effectiveness in the Irish-medium sector. (Contains 6 tables, 5 figures, and 1 note.)