Moon Sung-keun (Korean: 문성근; born May 28, 1953) is a South Korean actor and politician. He has won three Blue Dragon Film Awards, two Baeksang Arts Awards, and two Chunsa Film Art Awards for Best Actor.

Moon was born in Tokyo, Japan. His father was Rev. Moon Ik-hwan, who fought for democracy alongside Kim Dae-jung under the military regime led by Park Chung Hee in 1970s, and was a well-known pro-unification activist. After graduation from Sogang University with a bachelor's degree in International Business, Moon worked as a salaryman for eight years.