Guy Gavriel Kay is a Canadian writer of fantasy fiction. The majority of his novels take place in fictional settings 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. Kay has expressed a preference to avoid genre categorization of these works as historical fantasy. As of 2022, Kay has published 15 novels and a book of poetry. As of 2018, his fiction has been translated into at least 22 languages. Kay is also a qualified lawyer in Canada.

Historical fantasy is a category of fantasy and genre of historical fiction that incorporates fantastic elements into a more "realistic" narrative. There is much crossover with other subgenres of fantasy; those classed as Arthurian, Celtic, or Dark Ages could just as easily be placed in historical fantasy. Stories fitting this classification generally take place prior to the 20th century.