Duncan
- Clan Duncan
- Duncan (Paul Simon song)
- Duncan (Slim Dusty song)
- Duncan (given name)
- Duncan (horse)
- Duncan (mango)
- Duncan (surname)
- Duncan Dam
- Duncan Lake (British Columbia)
- Duncan Lake (Quebec)
- Duncan River
- Duncan River (New Zealand)
- Duncan Toys Company
- Duncan U. Fletcher High School
- Duncan, Arizona
- Duncan, British Columbia
- Duncan, Indiana
- Duncan, Iowa
- Duncan, Kentucky (disambiguation)
- Duncan, Mississippi
- Duncan, Missouri
- Duncan, Nebraska
- Duncan, North Carolina
- Duncan, Oklahoma
- Duncan, South Australia
- Duncan, South Carolina
- Duncanville, Alabama
- Duncanville, Illinois
- Duncanville, Texas
- Dunkin (disambiguation)
- HMS Duncan
- Hundred of Duncan
- Justice Duncan (disambiguation)
- Night Bugs
- Seymour Duncan
- USS Duncan