© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. In many countries, the performance of young people in upper secondary education helps determine whether or not they participate in higher education. One of the weaknesses in much of the literature in this area to date has been a focus on how potential determinants, such as socio-economic status, impact the conditional mean of secondary school performance. To address this, we instead examine the relationship between the distribution of upper secondary school performance and a range of individual and school-level characteristics using unconditional quantile regression methods and data from Ireland. We find that determinants such as parental occupation group, maternal unemployment, extra private tuition and working part-time have differential effects for low- and high-ability students and that important insights are lost by focussing on the conditional mean. The implication is that while certain factors can impact on whether or not a student is likely to proceed to higher education, other factors may affect where students go and what they study.