["Child and Adolescent Mental Health, EarlyView. ", "\n\nBackground\nSchool absence is associated with mental health problems in adolescents, but most studies are cross‐sectional. Longitudinal studies where school absence precedes mental health problems are needed to infer whether school absence is associated with later mental health problems. We aimed to investigate the association between school absence among 14‐ to 15‐year‐olds and later mental health problems at ages 16–17 in England.\n\n\nMethods\nA retrospective cohort study using an existing linkage between the Millennium Cohort Study (MCS) and the National Pupil Database (NPD), representing 8438 adolescents. We explored different absence thresholds and used logistic regression to examine associations between school absence and later mental health problems.\n\n\nResults\nA threshold of >10% of half‐day school sessions missed identified 18% of adolescents who reported mental health problems at follow‐up. At this threshold, high school absence was associated with increased odds of later mental health problems after adjusting for covariates (girls = 1.44, 95% CI 1.05–1.98; boys OR = 1.49, 95% CI 1.04–2.13). The strength of associations between absence and later mental health problems increased with longer durations of absence.\n\n\nConclusion\nWe found a longitudinal association between high levels of school absence (>10% of sessions) and later mental health problems in a nationally representative sample of adolescents in England. High levels of school absence can be used as an early marker of increased risk of mental health problems in the general population. School absence may contribute to the development of later mental health problems in adolescents.\n\n"]