A comprehensive school is a state school that does not select its intake on the basis of academic achievement or aptitude. This is in contrast to the selective school system, where admission is restricted on the basis of a selection criteria. The term is commonly used in relation to England and Wales, where comprehensive schools were introduced in 1965. It corresponds broadly to the German Gesamtschule and to the high school in the United States and Canada. About 90% of British pupils attend comprehensive schools.

Although comprehensive schools do not directly select pupils on the basis of academic ability, they may be part of a system in which selection occurs via catchment area. For example, school catchment areas containing expensive houses will be mainly populated by wealthy parents, whose children would be expected to show, on average, a high level of academic achievement at primary school. Most comprehensives are secondary schools for children between the ages of 11 to at least 19, but in a few areas there are comprehensive middle schools, and in some places the secondary level is divided into two, for students aged 11 to 14 and those aged 14 to 19, roughly corresponding to the US middle school (or junior high school) and high school, respectively.