O Se-chang (Korean: 오세창; Hanja: 吳世昌, 6 August 1864 – 16 April 1953), art name Wichang (위창; 葦滄; 韙傖), was a Korean politician, politician, writer, calligrapher-painter (서화가; 書畫家; seohwaga), and Korean independence activist.
He is known for his writings on Korean calligraphy-paintings and epigraphy, such as Geunyeok seohwi (근역서휘; 槿域書彙) and Geunyeok insu (근역인수; 槿域印藪), Geunyeok seohwajing (근역서화징; 槿域書畵徵), an encyclopaedia of Korean art history, as well as his active engagement in journalism, art, and politics.