Kim Sung-oh is a South Korean actor. He is best known for his supporting roles in the television series Secret Garden and the film The Man from Nowhere.

Secret Garden is a 2010 South Korean television drama starring Ha Ji-won, Hyun Bin, Yoon Sang-hyun, and Kim Sa-rang. It aired on SBS from November 13, 2010 to January 16, 2011, on Saturdays and Sundays at 22:00 (KST) for 20 episodes.