Sione Ngongo Kioa (born 14 April 1959)[1] is a Tongan diplomat and civil servant.

After graduating from Tailulu College, Ngongo attended the University of the South Pacific in Suva, Fiji, where he studied mathematics and economics,[2] and later earned his Doctor of Philosophy in Economics at the Australian National University in Canberra, Australia.

[3] From 2002 to 2005 Ngongo was General Manager of Leiola Duty Free Shops as well as the President of the Tonga Chamber of Commerce & Industries in Nuku’alofa.

His appointment as Tongan High Commissioner to the United Kingdom was announced by the Ministry of Foreign Affairs on 21 November 2005, replacing Viela Tupou in the post.

[2] He was also concurrently accredited as Ambassador Extraordinary and Plenipotentiary of Tonga to the Russian Federation,[4] Germany,[1] the Netherlands,[5] Denmark,[6] Italy,[7] Luxembourg,[8] Switzerland,[9] Belgium,[10] and the European Union.