Lady Susan is a selfish, attractive woman, who tries to trap the best possible husband while maintaining a relationship with a married man. She subverts all the standards of the romantic novel: she has an active role, she's not only beautiful but intelligent and witty, and her suitors are significantly younger than she is.

Although the ending includes a traditional reward for morality, Lady Susan herself is treated much more mildly than the adulteress in Mansfield Park.