A preparatory school, or prep school, is usually a secondary school (high school) designed to prepare a student for higher education. Often, such schools are very highly selective, accepting only a very small percentage of applicants. Such schools often have very high admissions fees which are used to attract and hire the best teachers, and also used to provide enriched learning environments and services such as libraries, science laboratories, and computers. Graduates of preparatory schools are often actively sought by colleges due to the colleges' confidence that the students will be better educated.

Some well known preparatory schools include:

In France, some high schools offer special postgraduate classes, equivalent in level to the first years of university, for students who wish to enter Grandes Écoles (see this word).