Aim. To establish levels of mental health at a community level and to model the relationship between mental health difficulty, health-related impact and health related quality of life in school pupils aged 11–18 years old. Background. The issue of psychosocial and mental health in school pupils is a topic of considerable academic and public interest. The incidence of mental health problems in children 11–18 years shows marked differences between countries and within countries. Much of the epidemiological literature has focused on diagnostic categories rather than population health. Design. The study employed a cross-sectional survey. Methods. A cross-sectional survey of 1786 school children aged 11–18 years was conducted in Scotland. Participants completed the strengths and difficulties questionnaire and the SF-10 for Children. Results. This group of school pupils had similar levels of mental health needs and psychosocial health status as UK and age-related US norms. They had poorer levels of physical health status. The most important predictors of psychosocial health status were difficulty category, impact, physical health status and chronicity. The most important predictors of impact were difficulty category, chronicity and psychosocial health status. Conclusion. There is a need to tackle psychosocial health problems in schools. Problems are often chronic in nature and whilst still having an impact on the life of pupils may not be severe enough for a diagnosis which would trigger treatment in the conventional sense. Psychosocial health is predicted by physical health therefore nursing interventions which are focussed on both physical and psychosocial health may be needed. Relevance to clinical practice. This study suggests that in some geographical areas in UK targeting of services to 'high-need' schools is not necessary and universal services are required. Problems need to be detected before they reach current treatment thresholds. Interventions should be school-based with a focus on impact on classroom learning and family difficulties.