John Duff (disambiguation)

John Duff (1895–1958) was a Canadian race car driver.

John Duff may also refer to:

• John Duff (counterfeiter) (1759–1799), American counterfeiter, hunter, and scout
• John Duff (singer) (born 1988), American pop singer
• John B. Duff (born 1931), former commissioner of The Chicago Public Library
• John Finlay Duff (1799–1868), captain of ship Africaine and businessman in South Australia
• John Wight Duff (1866–1944), Scottish classicist and academic