A common decision parents face is the choice of school for their children. In Ireland, somewhat uniquely in an international context, this choice includes a large number of state-funded single-sex schools, to the point that this can be considered a realistic option for many parents. Focusing on secondary-level education and using the PISA 2018 dataset, we examine whether different parental attitudes help explain the selection of single-sex versus coeducational schools in Ireland. Focusing on those households that have a degree of choice in secondary school selection, we find that parents who place a greater emphasis on factors such as religious ethos and academic achievement rather than subject choice or the climate of the school tend to have children in single-sex schools. The importance of a school's academic achievement seems to be particularly relevant for those from higher socioeconomic backgrounds.