The Unknown Quantity
- Blwyddyn: 1919
- Gwlad: United States of America
- Genre: Drama
- Stiwdio: Vitagraph Company of America
- Allweddair: lost film
- Cyfarwyddwr: Thomas R. Mills
- Cast: Corinne Griffith, Huntley Gordon, Harry Davenport, Jack McLean, Jack Ridgeway, F.R. Buckley
