Nangklao, or Rama III (31 March 1787 – 2 April 1851), is the third monarch of Siam under the House of Chakri, ruling from 21 July 1824 to 2 April 1851.

He succeeds his father, Buddha Loetla Nabhalai, as the King of Siam.

His succession is unusual according to the traditions because Jessadabodindra is a son of a concubine rather than a queen.

He surpasses Prince Mongkut, who is a legitimate son of Buddha Loetla Nabhalai born to Queen Srisuriyendra.

During Jessadabodindra's reign, military hegemony of Siam can be observed through a series of massive wars in Laos, Cambodia, and Vietnam.

Jessadabodindra is known for his affection of Chinese culture.

As a young prince, he is also known as a great businessman who conducts profitable trades with China and enriches the royal treasury.