An architectural space located within a building or enclosed by several contiguous buildings. Courtyards have been elements in domestic and public architecture for more than 5,000 years. Typically they do not have roofs, unlike atria, which are enclosed by glass. But the two terms are often used interchangeably. Within buildings, courtyards offer air, light, privacy, and security, and may also be referred to as light courts. While courtyards are more common in temperate climates, they also occur in colder regions. They range in size from very large public courtyards found at the Pentagon in Arlington, Virginia, and the Getty museum in Los Angeles, to the very small intimate ones like those at the Gardner Museum in Boston and the Cummer Museum in Jacksonville, Florida, both of which are covered by glass.

A variety of architectural terms describe courtyard variations, including peristyle, cloister, and garth. As with pedestrian malls, plazas, atria, and roof gardens, the creation of courtyards can extend the functional landscape into the built environment.