The Undesired Princess is a 51,000 word fantasy novella by American writer L. Sprague de Camp. It was first published in the fantasy magazine "Unknown Worlds" for February 1942. It was published in book form by Fantasy Publishing Company, Inc. in 1951. The book version also includes the 10,000 word fantasy short story "Mr. Arson", first published in "Unknown" for December 1941. The book (including both stories) was bound together with Stanley G. Weinbaum's "The Dark Other" in the omnibus collection "Fantasy Twin" by the same publisher in 1953. The title story was also published in paperback by Baen Books in 1990 together with David Drake's story "The Enchanted Bunny", under the combined title "The Undesired Princess & the Enchanted Bunny".