Phetracha (alternative spellings: Bedraja, P'etraja, Petraja, Petratcha; also called Phra Phetracha; 1632–1703) is a king of the Ayutthaya kingdom in Thailand, usurping the throne from his predecessor King Narai and founding the Ban Phlu Luang dynasty, the final one of the Ayutthaya kingdom.
Originally a member of king Narai's extended family (two of his relatives are among Narai's wives), he is a trusted councilor of Narai, and leader of the Royal Elephant Corps.
However, in 1688 he leads the Siamese revolution of 1688, has Narai's heirs executed, and by marrying Narai's only daughter takes the throne of Ayutthaya kingdom upon Narai's death.
He reverses the pro-Western policies of Narai, ejecting foreigners from the kingdom, and launchea the Siege of Bangkok, to exile all French troops from Siam.
As a result, Siam stays isolated from Western contact until the nineteenth century.