Margaret Frazer is a pen name of a duo historical novelists known for their series of mediaeval mysteries featuring the Benedictine nun Dame Frevisse. The first six Sister Frevisse books were written as a collaborative effort between Mary Monica Pulver Kuhfeld and Gail Frazer. The remainder are written by Gail Frazer alone. Several (but not all) of the books are set in or around St. Frideswide's, the nunnery in Oxfordshire in which Frevisse resides. The series features many historical figures. The first six Sister Frevisse books were written as a collaborative effort between Mary Monica Pulver Kuhfeld and Gail Frazer. The remainder are written by Gail Frazer alone.

It is interesting to note that the main character, Dame Frevisse, is related by marriage to Geoffrey Chaucer and is familiar with his famous Canterbury Tales. Frevisse's mother's sister is married to Thomas Chaucer, Geoffrey's son. Thomas and his daughter, Alice, the Countess of Suffolk are also characters in some of the books. Frazer has named several of her books after Chaucer's Tales but they are not re-tellings.

A second set of mysteries, set in the same time and places as the Dame Frevisse books, features the wandering player/minstrel Joliffe.

• The Novice’s Tale (1992)
• The Servant’s Tale (1993) (received an Edgar award nomination)
• The Outlaw’s Tale (1994)
• The Bishop’s Tale (1994)
• The Boy’s Tale (1995)
• The Murderer’s Tale (1996)
• The Prioress’ Tale (1997) (received an Edgar award nomination)
• The Maiden’s Tale (1998)
• The Reeve’s Tale (1999)
• The Squire’s Tale (2000)
• The Clerk's Tale (2002)
• The Bastard's Tale (2003), set in 1447, features the power struggle between the various players trying to influence Henry VI of England during the parliament held at Bury St. Edmunds. The "bastard" of the title is Arteys, illegitimate son of the Duke of Gloucester, who plays a pivotal role in the story.
• The Hunter's Tale (2004)
• The Widow's Tale (2005)
• The Sempster's Tale (2006)
• The Traitor's Tale (2007)

• A Play of Isaac (2004)
• A Play of Dux Moraud (2005)
• A Play of Knaves (2006)