"I told you I had an ex-wife, right?"

—John Sheppard

Nancy Sheppard was Lt. Colonel John Sheppard's ex-wife. She worked for Homeland Security in Washington D.C. and recently got promoted to a director there.

She was once married to John Sheppard, but after a while, the two barely saw each other, so they later divorced. Soon after, Sheppard joined the Atlantis expedition. Ronon Dex first heard that Sheppard was married to someone on the day Dr. Carson Beckett was killed. (ATL: "Sunday")

They met again four years after the divorce when Sheppard learned of his father died of a heart attack. She was seeing someone else, a probable colleague named Grant (who Sheppard thought was Greg). While hunting for Dr. Richard Poole's replicator, Sheppard managed to convince Nancy to find anything she could on Project Archetype. (ATL: "Outcast")