In the light of recent disciplinary reform in United States and United Kingdom schools, academic attention has increasingly focused on school punishment. Drawing on interviews with school staff in alternative and mainstream schools in the United States and the United Kingdom, we highlight differences in understandings and practices of school discipline. We argue that, in both countries, there is a mismatch between mainstream schools and alternative schools regarding approaches to punishment, techniques employed to manage student behaviour and supports given to students. While these disparities mirror what one would expect based on the distinct institutional arrangements and organizational priorities of alternative and mainstream schools, they pose particular problems for children transitioning between the two types of school. In this article, we raise a series of questions about the impact of these mismatches on children’s experiences and the potential for school disciplinary reform to achieve lasting results.