Kosan

Kosan may be:
 * Kosan County, a county in Kangwon Province, North Korea
 * Kosan Biosciences, American pharmaceuticals company
 * Ube Kosan Open, golf tournament played at the Ube 72 Country Club, Yamaguchi, Japan

People with the surname Kosan include:
 * Anja Kosan (born 2002), German rhythmic gymnast
 * Ismail Kosan (born 1948), German Politician