The Mahavihara (Pali for "Great Monastery") was for several centuries the center of Theravada Buddhism in Sri Lanka. It was founded by king Devanampiya Tissa (247–207 BCE) in his capital Anuradhapura. The Mahavihara was the place where Theravadin orthodoxy was established by monks such as Buddhaghosa. The monks living at the Mahavihara were referred to as mahaviharavasims.

The term was also applied to a number of the larger monasteries in India, among them Nalanda, Vikramashila, Odantipura, Somapura, Ratnagiri, and others.

The Mahavihara was destroyed during sectarian conflicts with the (Mahayana) monks of the Abhayagiri Vihara during the 4th century. These Mahayana monks incited King Mahasena to destruct the Mahavihara. As a result of this, a later king expelled the Mahayana monks from Sri Lanka.