American-born Ajahn Sumedho (Thai: อาจารย์สุเมโธ) (born July 25, 1934 ) is a seminal figure in the Thai Forest Tradition and Western Theravada Buddhism. The word "Ajahn" is not a proper name, but a title which means "Teacher" in Thai. He is also affectionately known among his students as "หลวงพ่อ" which means "Venerable Father" in Thai. He has been an ordained bhikkhu for 40 years, and is perhaps the most senior living Western Theravadin bhikkhu.