Fidelis Morgan is an English actress and writer. She has acted with the Royal Shakespeare Company, the National Theatre, in repertory in various British cities and in the West End transfer of Noël Coward's The Vortex.

She has written stage plays based on the novels Pamela and Hangover Square. Her non-fiction writing includes The Female Wits, the first study of female playwrights of the Restoration stage and biographies of women from the 17th and 18th centuries including Charlotte Charke. Her novels include the Countess Ashby de la Zouche series of historical crime mysteries including The Rival Queens.

Morgan was born in a gypsy caravan that stood in a corner of the grounds of the ancient Abbey of Amesbury, halfway between Stonehenge and Woodhenge. Her parents were displaced Liverpudlians, and her father found work as a dentist in Amesbury; her mother was a painter.

On television, she has been seen in As Time Goes By, Jeeves and Wooster, Dead Gorgeous and Mr Majeika. She has also directed a number of theatre productions including at some of the UK's most prestigious drama schools.

Morgan's novels include the Countess Ashby de la Zouche series of historical crime mysteries: Unnatural Fire (2000), The Rival Queens (2001), The Ambitious Stepmother (2002) and Fortune's Slave (2004). The Rival Queens was nominated for a Lefty Award for "the most humorous mystery novels published in the U.S. in 2002" by Left Coast Crime, California, in 2003.