Phyllis Ann Karr (born July 25, 1944) is an American author of fantasy, romances, mysteries, and non-fiction.

Karr's primary literary interests, reflected in both her fiction and non-fiction, include Arthurian legend, William Shakespeare, the Gilbert and Sullivan operettas, and L. Frank Baum's Oz books.

Her early works, including literary articles, poetry, and fantasy and mystery short stories, began appearing in the 1970s.

Her short works have been published in Ellery Queen's Mystery Magazine, Weird Tales, Marion Zimmer Bradley's Fantasy Magazine, The Gilbert & Sullivan Journal, The Savoyard, Library Review, Oziana, The Baum Bugle, and other journals, as well as various anthologies.

Karr's first novels were romances, including Lady Susan, an expansion of the work of the same name by Jane Austen.