Howard Green Duff (November 24, 1913 – July 8, 1990) was an American actor of film, television, stage, and radio.

Duff was born in Charleston, Washington, now a part of Bremerton. He graduated from Roosevelt High School in Seattle in 1932 where he began acting in school plays only after he was cut from the basketball team. His first film role was as an inmate in Brute Force. His other movies include The Naked City (1948), All My Sons (1948), Calamity Jane and Sam Bass (1949), Panic in the City (1968), In Search of America (1971), A Wedding (1978) and No Way Out (1987).