Background With evidence of rising need around mental health in young people, cuts in specialist health provision and increasing recognition of the central role of schools in supporting young people with mental health problems, it is important to understand the provision of mental health support currently available in schools, the nature of the relationship with health and other providers of child and adolescent mental health (CAMH) services, and what are the key barriers to accessing support. Method The study was a convenience sample survey of 577 school staff from 341 schools in England. Participants completed an online survey about the provision of specialist mental health support in their school, including what support is available, who provides it, and perceived barriers to supporting the mental health of young people. Data were linked to publicly available data on school characteristics. Results Over two thirds of schools reported having some specialist support available, with specialist provision more common in secondary schools. Staff training and whole‐school approaches were the most frequently employed specific approaches. Support was most often provided by educational psychologists, followed by counsellors. School staff particularly valued support and feedback within the schools context. The most frequently cited barrier to mental health support was the limited capacity of specialist CAMH services. Conclusions The results suggest a need to enhance the availability of specialist support for mental health both within schools and in CAMH services.