Jack Shephard is one of the main protagonists of Lost, and thus his family is central to the series and its stories.
- Jack Shephard - A highly successful spinal surgeon that crashed on Oceanic Flight 815 while taking his father's body to Los Angeles from Australia.
- Christian Shephard - Jack's alcoholic father that was also a successful spinal surgeon. He died in an alleyway after going on a drinking binge in Australia.
- Margo Shephard - Jack's mother that forced him to go to Australia to find his father.
- Sarah Wagner - Jack's ex-wife that started to have an affair.
- Claire Littleton - Jack's illegitimate half-sister who crashed with him on Oceanic Flight 815.
- Aaron Littleton - Jack's half-nephew who was born on The Island.
- Ray Shephard - Jack's maternal grandfather who attempted to escape from his care home.
- Kate Austen - Jack's ex-fiancé whom he met when he crashed on The Island.
- Juliet Burke - Jack's past romance and ex-wife in the flash-sideways.
- David Shephard - Jack's son in the flash-sideways timeline who acted as a prop to help him let go of his parental issues.
Note: Claire's family, Kate's family and Juliet's family intertwine with Jack's.
|Portrayed by Matthew Fox and John O'Hara|
|Shared and non-centric flashes|