Ajahn Brahm (born Peter Betts on 7 August 1951) is a British-born Buddhist monk.

Ordained in 1974, he trained in the Thai Forest Tradition of Theravada Buddhism under his teacher Ajahn Chah. Currently, Ajahn Brahm is the abbot of Bodhinyana Monastery in Serpentine, Western Australia, and serves as an adviser or patron of various Buddhist organizations in Australia, Singapore, and the UK.

Coming from a working-class background, Ajahn Brahm won a scholarship to study Theoretical Physics at Cambridge University in the late 1960s. After graduating from Cambridge, he taught high school for one year before traveling to Thailand to become a monk. During his early years as a junior monk, he compiled an English-language guide to the Buddhist monastic code - the Vinaya - which later became the basis for monastic discipline in many Theravadan monasteries in Western countries.