Sisavang Phoulivong (or Sisavangvong, Lao: ພຣະບາທສົມເດັຈພຣະເຈົ້າມະຫາຊີວິຕສີສວ່າງວົງສ໌) (14 July 1885 – 29 October 1959) was king of the Kingdom of Luang Phrabang and later the Kingdom of Laos from 28 April 1904 until his death on 29 October 1959.
He was born at Luang Phrabang on 14 July 1885. His father was Zakarine, King of Luang Phrabang and his mother was Queen Thongsy. He was educated at Lycée Chasseloup-Laubat, Saigon and l'École Coloniale, Paris.
He succeeded his father as King of Luang Prabang after the death of his father, 25 March 1904. Luang Phrabang was then a French protectorate within French Indochina. He ascended the throne, at the Royal Palace, Luang Prabang, 15 April 1904, and was crowned there, 4 March 1905. He led the country into independence from French Indochina in 1953. In 1954 he celebrated his Golden Jubilee, becoming the longest-reigning king in Asia until King Bhumibol Adulyadej of Thailand, who surpassed his reign in 2001.
After illness he passed away and was ceremoniously cremated and buried in That Luang in 1961. His funeral procession was transported by the royal funeral carriage, a 12-metre-high wooden hearse with a carved seven-headed serpent. Many representatives were at the state funeral including Prince Bhanubandhu Yugala, who represented Thailand.
Sisavangvong University was named in his honour and statues erected in his memory.