The Eternals are a race of humanoids appearing in American comic books published by Marvel Comics. They were created by Jack Kirby, making their first appearance in The Eternals #1 (July 1976).

In the Marvel Universe, the Eternals are an offshoot of humanity known as Homo immortalis which were created one million years ago by the enigmatic alien Celestials to defend Earth with their superhuman powers and abilities. Their primary adversaries are the Deviants, who share a similar origin and pose a regular threat to humanity. Due to their virtual immortality, Eternals have largely secluded themselves from humans, with their god-like status forming the basis of various mythological figures around the world.

Since their appearance, the Eternals have had several of their own series, in addition to crossing into other titles, such as Thor and X-Men. They made their live action film debut in the Marvel Cinematic Universe with their own feature film Eternals, directed by Chloé Zhao, which was released November 5, 2021.

In 1970, Jack Kirby left Marvel Comics to work at DC Comics, where he began the saga of the New Gods, an epic story involving mythological and science fiction concepts. Though he had planned for a definitive ending, the series was abruptly cancelled. Upon his return to Marvel, Kirby continued exploring his interest in mythological science fiction through The Eternals.

Originally titled "The Celestials", Marvel changed the title to "Return of the Gods", whose comic book cover bore stylistics similarities to Erich von Daniken's book Chariots of the Gods?. To avoid potential legal issues, the name was again changed to “Eternals". The Eternals' saga was thematically similar to the New Gods' and it shared the same fate: Kirby's new series also was eventually canceled without resolving many of its plots. Writers Roy Thomas and Mark Gruenwald used the Eternals in a Thor storyline that concluded in Thor #301, resolving those lingering plotlines. Subsequent to the Thor storyline, the Eternals (and the mythology connected to them) have appeared or been mentioned in numerous Marvel comics. In particular, the Celestials' experiment on humanity has been used to explain how certain humans can develop super-powers. The Titanians (created by Jim Starlin) and Uranians (created by Stan Lee) were later retconned as being Eternals as well.

The Eternals returned for a 12-issue miniseries in 1985 under writer Peter B. Gillis and penciler Sal Buscema. According to comic-book historian Peter Sanderson, "editor in chief Jim Shooter disliked Gillis's scripts, so Walter Simonson wrote the final four issues."

In 2000, a one-shot comic called New Eternals: Apocalypse Now #1 featured an older conflict between the Eternals and X-Men villain Apocalypse. In 2003, writer Chuck Austen and artist Kev Walker rebooted the franchise for Marvel's mature readers-focused MAX imprint, resulting in The Eternal.

The Eternal series from Marvel's MAX imprint written by Chuck Austen was based on an idea he had been working on for a while: "I pitched this back when I first started working at Marvel, but Joe Quesada was against doing it. He saw no future in this particular old Kirby concept." Austen described the plot as involving "Ikaeden, the leader of the Eternals, who arrives on Earth at the dawn of man, and evolves humankind from Homo erectus so he can use them as slaves to mine raw materials for the Celestials, his bosses, basically," as well as "Kurassus, who is the second-in-command of the mining mission, and who is determined to undermine Ikaeden and kill Ikaeden's precious slave-girl and son." In an interview with Newsarama he gave an outline of his planned plot: