Gwyneth and the Thief is a young adult historical romance novel written by Margaret Moore and published by Avon Books in 2002 as part of the Avon True Romance series.
The novel is set in Medieval England and is about the relationship between Gwyneth, a fifteen-year-old noblewoman, and Gavin, a young man who became a thief because of a life of poverty after being born illegitimately. Gwyneth's mother is dead and she is the only living child of her father, who is seriously ill. Because of this, Gwyneth must take on the responsibilities of running the family's manor, Haverleigh. Gwyneth's cruel neighbor, Baron DeVilliers, wants Haverleigh for his own, and hopes to take advantage of the situation by forcing Gwyneth to marry him. When Gwyneth finds Gavin hurt in the woods she sees him as a solution to her problems. He is an able fighter and she decides to rescue him on the condition he teach the men of Haverleigh to fight. However despite the business nature of the arrangement and their different social statuses, the two teenagers soon find themselves falling in love with each other.