Yun Posun, South Korean activist and politician, 2nd President of South Korea (d. 1990)
Yun Posun (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.

Having entered politics after World War II, Yun served as Secretary to Korea's Chief of Staff in 1947; and was Mayor of Seoul in 1948. He served as Commerce Minister for the newly liberated Korea from 1949 to 1950. In 1955 Yun helped establish the South Korean Democratic Party. He was forced to resign the presidency by Park Chung-hee as a result of the May 16 coup in 1961.