A comprehensive school typically is a secondary school for pupils aged approximately 11–18, that does not select its intake on the basis of academic achievement or aptitude, in contrast to a selective school system where admission is restricted on the basis of selection criteria, usually academic performance. The term is commonly used in relation to England and Wales, where comprehensive schools were introduced as state schools on an experimental basis in the 1940s and became more widespread from 1965. They may be part of a local education authority or be a self governing academy or part of a multi-academy trust.

About 90% of English secondary school pupils attend a comprehensive school (academy schools, community schools, faith schools, foundation schools, free schools, studio schools, university technical colleges, state boarding schools, City Technology Colleges, etc.). Specialist schools may also select up to 10% of their intake for aptitude in their specialism. A school may have a few specialisms, like arts (media, performing arts, visual arts), business and enterprise, engineering, humanities, languages, mathematics, computing, music, science, sports, and technology. They are not permitted to select on academic ability generally.

There were over 24,323 schools in England in 2018. There were 391 nurseries, 16,769 primary schools, 3,448 secondary schools, 2,319 independent schools, 1,044 special schools and 352 pupil referral units (PRUs). In Wales there were 1,569 schools. There were 9 nursery schools, 1,238 primary schools, 19 middle schools, 187 secondary schools, 75 independent schools and 41 special schools. Comprehensive schools correspond broadly to the public school in the United States, Canada and Australia.