Tantric Theravada (also, "Esoteric Southern Buddhism") is a term used to refer to certain Tantric practices, views and texts within Theravada Buddhism. L.S. Cousins defines this tradition as "a type of Southern Buddhism which links magical and, ritual practices to a theoretical systematisation of the Buddhist path itself", though he feels the term Tantric is a too specific term to be used. One specific kind of Tantric Theravada is termed the Yogāvacara tradition and this kind of esoteric Buddhism is most widely practiced today in Cambodia and Laos and in the pre-modern era was a major Buddhist current in Southeast Asia. In the west, the study of Tantric Theravada was pioneered by professor François Bizot and his colleagues at the École française d'Extrême-Orient with a particular focus on the material found at Angkor.
Historically, the Buddhists of Abhayagiri vihāra in Sri Lanka are known to have practiced Tantric Vajrayana and Mahayana and this might have had an influence on Southeast Asia through their missionary work in Java. Ari Buddhism was a form of Buddhism practiced in the Mon kingdoms of Burma which also contained Tantric elements borrowed from India and local Nat (spirit) and Nāga worship. In many of Bizot's works there is some suggestion that the Buddhism of the Mon may have influenced the later Yogāvacara tradition. It is also possible that Southeast Asian Buddhism was influenced by the practice of Hinduism and Mahayana Buddhism which flourished in Southeast Asia during the time of the Khmer Empire. According to Lance Cousins, it is also possible that 'Tantric Theravada' developed within the "orthodox" Mahavihara tradition of Sri Lanka, citing the 5th century Buddhist scholar Buddhagosa's mention of secret texts (gulhagantham) as well as other textual evidence from the Pali commentaries. Cousins concludes that "It is quite possible that present-day esoteric Buddhism contains ideas and practices deriving from more than one of these sources. Nevertheless it is certainly premature to assume that it has its origins in unorthodox circles."