Theravāda (/ˌtɛrəˈvɑːdə/; Pāli, lit. "School of the Elders")[1][2] is the most commonly accepted name of Buddhism's oldest existing school.[1][2] The school's adherents, termed Theravādins, have preserved their version of Gautama Buddha's teaching or Buddha Dhamma in the Pāli Canon for over a millennium.[1][2][web 1]

The Pāli Canon is the most complete Buddhist canon surviving in a classical Indian language, Pāli, which serves as the school's sacred language[2] and lingua franca.[3] In contrast to Mahāyāna and Vajrayāna, Theravāda tends to be conservative in matters of doctrine (pariyatti) and monastic discipline (vinaya).[4] One element of this conservatism is the fact that Theravāda rejects the authenticity of the Mahayana sutras (which appeared c. 1st century BCE onwards).[5][6]

Modern Theravāda derives from the Mahāvihāra order, a Sri Lankan branch of the Vibhajjavāda tradition, who are in turn a sect of the Indian Sthavira Nikaya. This tradition began to establish itself in Sri Lanka from the 3rd century BCE onwards. It was in Sri Lanka that the Pāli Canon was written down and the school's commentary literature developed. From Sri Lanka, the Theravāda Mahāvihāra tradition subsequently spread to the rest of Southeast Asia.[7] It is the dominant religion in Cambodia, Laos, Myanmar, Sri Lanka, and Thailand and is practiced by minorities in India, Bangladesh, China, Nepal, and Vietnam. The diaspora of all of these groups, as well as converts around the world, also embrace and practice Theravāda Buddhism.

During the modern era, new developments have included Buddhist modernism, the Vipassana movement which reinvigorated Theravāda meditation practice,[web 1] the growth of the Thai Forest Tradition which reemphasized forest monasticism and the spread of Theravāda to other Asian and western countries such as India, Nepal, several European countries and the United States by immigrants and converts.