Geolseong Yun Chi-ho (윤치호; 尹致昊; also known by a pen name Chwa-ong, December 26, 1864 – December 9, 1948) was a Korean nationalist activist and one of early prominent leaders of Korean independence movement. He was a strong supporter for reform and modernization of Joseon Dynasty during the end of 19th century. He also took a part on the opposition movement against the partition of Korea following the end of Russo-Japanese War and helped to found the New People's Association in 1901.
After the Japanese Revolution of 1918 and the Korean independence movement of 1919, Yun was elected to the National Congress of Korea in 1922. Yun then served as the first Minister of Education of Korea from 1922 to 1924 and the Prime Minister of Korea from 1924 to 1927. He then elected as the second President of the Republic of Korea from 1935 to his death in 1948.
During his tenure, Korea experienced a period of rapid industrialization and modernization, the conflicts with China during World War II and became one of the founding countries of the United Nations. For his role on the independence activism, Yun was referred as the "Grand Old Man of Korea" (웅대한 원로, Ungdaehan Wonro). Following his death in 1948, he was posthumously granted the honorific Geolseong (傑聖, literally, "Illustrious Sage") by the National Congress of Korea.