Nightfall is an influential science fiction short story by the late Isaac Asimov. It was first published in the September 1941 issue of Astounding Science Fiction magazine under editor John W. Campbell. According to Asimov's autobiography, Campbell ordered Asimov to write the story after discussing with him a quotation from Ralph Waldo Emerson:

If the stars should appear one night in a thousand years, how would men believe and adore and preserve for many generations the remembrance of the city of God!

The story is set on a fictional planet, Lagash, located in a stellar system containing six stars. The "nightfall" of the title occurs only once every two thousand and fifty years when the sole sun remaining above the horizon is occulted by a planetary body not directly observable to the planet's inhabitants. The impending approach of nightfall has the populace in a panic, fearing the end of their civilization.

Considered a classic of the genre, "Nightfall" has been anthologized no fewer than two dozen times, and has appeared in at least another half-dozen collections of Asimov's older stories.

In 1988, a low-budget movie was produced based upon the story. However, its script, while retaining the story's basic premise, deviated wildly from the original plot, and the film was roundly dismissed by critics and ridiculed by science fiction fans. Asimov himself disowned it.

In 1990, two years before Asimov's death, he collaborated with author Robert Silverberg on a novel-length revision of the original story. In fifty years, much about the original — despite its classic status — had become dated both scientifically and in terms of literary style. The novel significantly expands upon and updates the original premise. It was a commercial success but received mixed reviews.


Nightfall is also the name of a female elf character in Wendy and Richard Pini's comic book series, Elfquest. It is tempting to think that the character may have been named after the Isaac Asimov story, but the Pinis have never confirmed this.

Nightfall Games, creators of SLA Industries were not named after the Asimov story.