Sir John James Duncan was a politician in the colony and State of South Australia.
- Occupation
- politician, farmer, business executive, clerk
- Position held
- Member of the South Australian Legislative Council, Member of the South Australian Legislative Council, Member of the South Australian Legislative Council, Member of the South Australian House of Assembly
- Citizenship
- Australia, United Kingdom of Great Britain and Ireland
- Born
- February 12, 1845
- Died
- October 8, 1913