Frank Duncan may refer to:
Sports Frank Duncan (American football) (born 1956), American football player Frank Duncan (catcher) (1901–1973), American baseball player and manager in the Negro leagues from 1920 to 1948 Frank Duncan (outfielder) (1888–1958), American baseball player and manager in the Negro leagues Frank Duncan (pitcher) (1920–1999), American baseball player in the Negro leagues from 1941 to 1945
Others Frank I. Duncan (1858–1946), American politician, lawyer, judge and newspaper publisher