"Nightfall" is a 1941 science fiction short story by the American writer Isaac Asimov about the coming of darkness to the people of a planet ordinarily illuminated by sunlight at all times. It was adapted into a novel with Robert Silverberg in 1990. The short story has been included in large number of anthologies and has appeared in six collections of Asimov's stories. In 1968, the Science Fiction Writers of America voted "Nightfall" the best science fiction short story written prior to the 1965 establishment of the Nebula Awards and included it in "The Science Fiction Hall of Fame Volume One, 1929–1964".