"Christmas on Ganymede" is a science fiction short story by Isaac Asimov. It was written in December 1940, first published in the January 1942 issue of Startling Stories, and reprinted in the 1972 collection The Early Asimov and the anthology Christmas on Ganymede and Other Stories, edited by Martin H. Greenberg. It was the twenty-sixth story written by Asimov, and the nineteenth to be published. "Christmas on Ganymede" was later included in an early Foundation Series timeline that was published in Thrilling Wonder Stories along with the story "The Portable Star".