Innocence Undone is an American romance novel by Kat Martin. It was published in 1997 by St. Martin's Press, and is part of Martin's Kingsland series.
The novel is set in Georgian-era England, and centers around Jessie Fox, the daughter of a prostitute, being taken in by the old Marquess of Belmore to be raised as a lady. The Marquess intends to have the Jessie marry his son Matthew, a Navy captain, so that they can both inherit the Belmore title after he passes. Matthew, knowing Jessie's reputation as a street child, believes that Jessie is manipulating his father into treating her like a lady, while Jessie fears that her true backstory will be discovered by the public and tarnish the Belmore name.