Phra Sunthorn Vohara (Phu) (Thai: พระสุนทรโวหาร (ภู่), RTGS: Phra Sunthonwohan (Phu), pronounced [pʰá.sǔn.tʰɔ̄ːn.woː.hǎːn.pʰûː]; 26 June 1786 – 1855), known as Sunthorn Phu (Thai: สุนทรภู่, RTGS: Sunthonphu, pronounced [sǔn.tʰɔ̄ːn.pʰûː]), is Thailand's best-known royal poet. He wrote during the Rattanakosin period.

Phra Bat Somdet Phra Phutthaloetla Naphalai, personal name Chim, also styled as Rama II, was the second monarch of Siam under the Chakri dynasty, ruling from 1809 to 1824. In 1809, Itsarasunthon succeeded his father Rama I, the founder of Chakri dynasty, as Loetlanaphalai the King of Siam. His reign was largely peaceful, devoid of major conflicts. His reign was known as the "Golden Age of Rattanakosin Literature" as Loetlanaphalai was patron to a number of poets in his court and the King himself was a renowned poet and artist. The most notable poet in his employ was the illustrious Sunthorn Phu, the author of Phra Aphai Mani. The rapid growth of the number of his descendants was outstanding: he is believed to have had over 240 grandchildren.