As a setting where children and adolescents live and learn, linked to the family and embedded within the wider community, schools have an important influence on every student's health. Many health interventions have used schools as a platform, often for standalone programmatic initiatives to reduce health risks, and sometimes for more comprehensive approaches, but the interventions, uptake, and sustainability are generally disappointing. Evidence shows that, to improve health and to reduce inequality, all students must attend school from a young age and for as long as possible, and their educational success therein must be maximised. Thus, beyond educational benefits, schools are also important for health. Coherence between each school's policies, structures and systems, human resources, and practices is required to advance both academic and health outcomes. Beyond simply implementing ready-made programmes into schools, health professionals can position themselves as catalysts for structural change as they have many opportunities to advocate for, and participate in, the intersectoral implementation of reforms and innovations in school systems to promote the health of all students.