Stig Kjell Olof (Ola) Ullsten, (23 June 1931 in Umeå, Sweden – 28 May 2018) was a Swedish former politician and diplomat. He served as the Prime Minister of Sweden from 1978 to 1979 He was also the leader of the Liberal People's Party from 1978 to 1983. He also served as Deputy Prime Minister briefly in 1978 and then again from 1980 to 1982. He was also the Swedish foreign minister between 1979 and 1982.