Somdet Phra Narai (1633 - 11 July 1688) or Somdet Phra Ramathibodi III was the king of Ayutthaya from 1656 to 1688. His reign was the most prosperous during the Ayutthaya period and saw great commercial and diplomatic activities with foreign nations including the Persians and the West.

During the latter years of his reign, Narai gave the Greek adventurer Constantine Phaulkon so much power that technically he became the chancellor of the state. Through Phaulkon's arrangements, the Siamese kingdom came into close diplomatic relations with the court of Louis XIV and French soldiers and missionaries filled the Siamese aristocracy and defense. The dominance of French officials led to frictions between them and the native mandarins and led to the turbulent revolution of 1688 towards the end of his reign. Narai??? reign was also known for a small war with England in 1687 and the invasion of Burmese Lanna in 1662.