Jack may refer to:
- Jack Carroll, an Old Earth engineer.
- Jack Damana, an officer of the RMN Office of Naval Intelligence.
- Jack Frazier, an officer of the Royal Manticoran Navy.
- Jack Fuentes, an Erewhonese businessman and politician.
- Jack Hammond, another officer of the Royal Manticoran Navy.
- Jack Hardesty, an officer of the Grayson Space Navy.
- Jack McBryde, a Mesan security officer.
- You may also be looking for Jackson.