Siaosi Tupou II, King of Tonga (George Tupou II in English) was the King of Tonga from 18 February 1893 until his death. He was officially crowned at Nukuʻalofa, on 17 March 1893. He was also the 20th Tuʻi Kanokupolu. In Tonga itself he was better known under the Tongan version of his name Jiaoji Tubou (Siaosi Tupou in modern spelling) or even Tāufaʻāhau Tupou II.
Siaosi Tupou II was the son of Prince Tuʻi Pelehake (Fatafehi Toutaitokotaha) also Prime Minister of Tonga in 1905), whose mother Sālote Pilolevu was a daughter of Tāufaʻāhau Tupou I, and he was the son of Fusipala Taukiʻonetuku, a daughter of Tēvita ʻUnga who was a son of Tāufaʻāhau Tupou I again: George Tupou I that is, the founder of the united Tongan kingdom.
He ascended the throne at the age of 18, upon the death of his great-grandfather George Tupou I, at which time he was still a bachelor. In 1896, the chiefs of the country urged him to marry and produce an heir. On 1 June 1899, he took Lavinia Veiongo (1879–1902) as wife. She was the daughter of Kupuavanua from Vavaʻu and Tōkanga from Niuafoʻou, thus obliging these islands to the throne. Queen Lavinia died on 25 April 1902 from tuberculosis, leaving one child, Sālote (born 13 March 1900), the future Queen.