Abstract
The substantial time that children and young people spend in schools makes them important sites to trial and embed prevention and early intervention programmes. However, schools are complex settings, and it can be difficult to maintain school engagement in research trials; many projects experience high levels of attrition. This commentary presents learning from two large-scale, mixed-methods mental health intervention trials in English schools. The paper explores the barriers and challenges to engaging schools in promotion or early intervention research and offers detailed recommendations for other researchers.