Setthathirath (Lao: ເສດຖາທິຣາດ; 1534–1572) is considered one of the great leaders in Lao history. Throughout 1560s until his death, he successfully defended his kingdom of Lan Xang against military campaigns of Burmese conqueror Bayinnaung, who had already subdued Xieng Mai (Chiang Mai) in 1558 and Ayutthaya in 1564. Setthathirath was a prolific builder and erected many Buddhist monuments including Wat Xieng Thong in Louang Phrabang and the That Luang in Vientiane.
Also known as Chaiyachettha or Chaiyaset or Jayajestha, he was crowned King of Lanna after the death of his grandfather, the previous King Ketklao, who died without a male heir to the throne. His daughter Princess Yotkamtip was Chao Settathirath's Mother, which through succession made Prince Settathirath the Heir to the throne of Chiang Mai.
Son of the King Phra Chao Photisarath of Lan Xang, he became ruler of Chiang Mai in 1546. The previous ruler, King Ketklao, gave his daughter Princess Nang Yotkham in marriage to Phra Chao Phothisarath, and she bore him the Prince Chao Chaiyaset. When Ketklao died, there was no other descendant to succeed him.