"A Martian Odyssey" is a science fiction short story by American writer Stanley G. Weinbaum originally published in the July 1934 issue of Wonder Stories. It was Weinbaum's second published story (in 1933 he had sold a romantic novel, The Lady Dances, to King Features Syndicate under the pseudonym Marge Stanley), and remains his best known. It was followed four months later by a sequel, "Valley of Dreams". These are the only stories by Weinbaum set on Mars.