Co-institutional schools employ a style of schooling wherein both male and female students study on the same campus but classes are single-gender. Usually each division has its own building but may, on few occasions, use the facilities of the other division. Each division has its own administration and maintains its own courses, dress code, schedule, and other aspects. The two divisions may often share the same name.

This system is founded on the belief that students learn better in a single-gender environment. A co-institutional school differs from a single-sex school because it offers closer interaction between the two genders. Activities such as track and field

Track and field

Track and field is a sport comprising various competitive athletic contests based around the activities of running, jumping and throwing. The name of the sport derives from the venue for the competitions: a stadium which features an oval running track surrounding a grassy area...

, theater, cross country

Cross country running

Cross country running is a sport in which people run a race on open-air courses over natural terrain. The course, typically long, may include surfaces of grass and earth, pass through woodlands and open country, and include hills, flat ground and sometimes gravel road...

, model UN, ultimate

Ultimate (sport)

Ultimate is a sport played with a 175 gram flying disc. The object of the game is to score points by passing the disc to a player in the opposing end zone, similar to an end zone in American football or rugby...

, mock trial

Mock trial

A Mock Trial is an act or imitation trial. It is similar to a moot court, but mock trials simulate lower-court trials, while moot court simulates appellate court hearings. Attorneys preparing for a real trial might use a mock trial consisting of volunteers as role players to test theories or...

, speech and debate, and multi-cultural clubs are more successful under this system than they might otherwise be at a single-sex school.

One of the most prominent schools of this kind is Regis Jesuit High School

Regis Jesuit High School

Regis Jesuit High School is a Jesuit Catholic college preparatory high school located in Aurora, Colorado. Founded in 1877, the high school shares much of its history with its counterpart Regis University in neighboring Denver, Colorado....

 outside of Denver, Colorado

Denver, Colorado

The City and County of Denver is the capital and the most populous city of the U.S. state of Colorado. Denver is a consolidated city-county, located in the South Platte River Valley on the western edge of the High Plains just east of the Front Range of the Rocky Mountains...

, the only Jesuit school in the United States that follows this model.