Yun Po-sun (Korean: 윤보선; Hanja: 尹潽善; Korean pronunciation: [junbosʌn] or [jun] [posʌn]; August 26, 1897 – July 18, 1990) was a South Korean politician and activist who served as the second president of South Korea from 1960 to 1962. He was the only president of the parliamentary Second Republic of Korea.