Sione Tui Kleiss (often written Kleis, died 1979) was a Tuvaluan civil servant, priest and politician.
Kleiss was educated at Elisefou school on Vaitupu island, before studying in Western Samoa, New Zealand and Italy.
[1] He initially worked in the civil service, before becoming the first Gilbert and Ellice Islander to be ordained as a Roman Catholic priest in 1961.
He was re-elected to a reconstituted Legislative Council in the 1971 elections, representing the Nui constituency.
[3] However, in January 1975 he was asked to resign his ministerial role to become the Chief Minister's Advisor on Ellice Affairs.