Guy Gavriel Kay is a Canadian author of fantasy fiction. Many of his novels are set in fictional realms that resemble real places during real historical periods, such as Constantinople during the reign of Justinian I or Spain during the time of El Cid. These works are published and marketed as historical fantasy, though the author himself has expressed a preference to shy away from genre categorization when possible.

As of 2022, Kay has published 15 novels and a book of poetry. His fiction has been translated into at least 22 languages. Besides being an accomplished writer, Kay is also a qualified lawyer in Canada.