Somdej Toh (1788-1872; B.E. 2331-2415), known formally as Phra Buddhacharn Toh Phomarangsi, was one of the most famous Buddhist monks during Thailand's Rattanakosin Period. Born in Kumpangpetch province, he was, by some accounts, the son of King Rama I. He studied the Buddhist scriptures of the Pāli Canon with several Buddhist masters. After becoming a well-known monk, he became the preceptor for Prince Mongkut, later King Rama IV, when Mongkut became a monk. It was during Rama IV's reign that Somdej Toh was given the ceremonial name Phra Buddhacharn Toh Phomarangsi; during this time, Toh was living in Wat Rakang Kositaram. He was noted for the skill of his preaching and his use of Thai poetry to reflect the beauty of Buddhism.
He also appears in many versions of the story of Nang Nak.