|Family||Sister - Theresa Spencer|
|Played By||Imelda Corcoran|
Abigail Spencer is the sister of Theresa Spencer, the former girlfriend of Daniel Faraday. Desmond Hume meets her when he goes back to Oxford to get in contact with Daniel's mother. She invites Desmond into the house to see her sister, but Desmond doesn't realize that Theresa is not well. She informs Desmond that Charles Widmore has been paying for Theresa's treatment.