Senator Duncan may refer to:
Alexander Duncan (politician) (1788–1853), Ohio State Senate J. Ebb Duncan (1909–1980), Georgia State Senate James H. Duncan (1793–1869), Massachusetts State Senate Jim Duncan (Alaska politician) (born 1942), Alaska State Senate Joseph Duncan (politician) (1794–1844), Illinois State Senate Robert L. Duncan (born 1953), Texas State Senate Thomas Duncan (American politician) (1893–1959), Wisconsin State Senate Verne Duncan (born 1934), Oregon State Senate William C. Duncan (1820–1877), Michigan State Senate
See also Senator Dungan (disambiguation)