Gerald Koh Mun Yew (born 20 June 1978) is a Singaporean former backstroke, freestyle and medley swimmer. He competed in five events at the 1996 Summer Olympics.
Koh won the bronze medal in the 200m backstroke at the 2001 Southeast Asian Games.
Koh retired from competitive swimming in 2003.
Koh has an elder brother, Desmond Koh, who is also a former swimmer for Singapore.