The Legend of King Naresuan (Thai: ตำนานสมเด็จพระนเรศวรมหาราช; RTGS: Tamnan Somdet Phra Naresuan Maha Rat) is a Thai biographical historical drama film series about King Naresuan the Great, who ruled Siam from 1590 until his death in 1605.

The films are directed by Chatrichalerm Yukol and are a followup to his 2003 film, The Legend of Suriyothai. The films were released in the U.S. under the titles Kingdom of War.

The Legend of King Naresuan The Great, Part I, Hongsawadee's Hostage, was released on January 18, 2007.

The Legend of King Naresuan The Great, Part II, Reclaiming Sovereignty, was released on February 15, 2007.

The Legend of King Naresuan The Great, Part III, Naval Battle, was released on March 31, 2011.

The Legend of King Naresuan The Great, Part IV, The Nanda Bayin War, was released on August 11, 2011.

The Legend of King Naresuan The Great, Part V, Elephant Battle, was released on May 29, 2014.

The Legend of King Naresuan The Great, Part VI, The end of Hong Sa, was released on April 9, 2015.

Part I deals with Naresuan's boyhood, when he was taken hostage by Burmese King, Bayinnaung to keep the vassal Ayutthaya Kingdom subservient. During this time, he was a novice Buddhist monk under the tutelage of a wise father-figure monk (Sorapong Chatree). Part II depicts Naresuan as a young adult prince, already a formidable military strategist, as he leads his army on exploits against breakaway kingdoms for King Bayinnaung's successor, King Nonthabureng, and eventually breaks away to declare sovereignty for Siam. Part III was to depict Naresuan's military and leadership skills and the expansion of the Siamese kingdom.

In production for more than three years, the project has an estimated budget of 700 million baht, making it the most expensive Thai film made.

As King of Fire, part II was selected as Thailand's submission to the 80th Academy Awards for Best Foreign Language Film.