
The planet Neptune has been used as a reference and setting in various films and works of fiction:In H. G. Wells's short story "The Star", Neptune is destroyed in a collision with another supermassive object which reduces its orbital velocity to zero; the wreckage falls into the Sun, narrowly missing Earth. In the Captain Future series, Neptune is portrayed as a sea planet, not out of any scientific theory but evidently because Neptune is the Roman sea god. In Olaf Stapledon's 1930 epic novel Last and First Men, Neptune is the final home of the highly evolved human race. The planet is depicted as having a dense atmosphere but with a solid surface. In Hugh Walters' 1968 novel Nearly Neptune, the first manned expedition to Neptune ends in apparent disaster as a fire destroys vital equipment on board the spacecraft as it nears the planet. In the 1973 television series Ultraman Taro an amalgam of past monsters form into the monster Tyrant on Neptune where he begins his rampage until he is stopped by the titular hero on Earth. While on Neptune he easily defeats the commander of the Ultra Brothers, Zoffy. Notably all the gas giants and Mars are depicted as barren rock-like worlds with no atmosphere. The majority of the 1997 science fiction horror film Event Horizon takes place in orbit around Neptune with the eponymous space ship Event Horizon reappearing in a decaying orbit around Neptune after a seven year disappearance. In the 2019 science fiction movie Ad Astra Neptune is the destination of the protagonist, who wants to stop destructive waves of antimatter coming from a malfunctioning space station that orbits the planet. In Call of Duty: Infinite Warfare, Neptune is the setting for the multiplayer map, Frontier, which takes place on a space station orbiting the planet. The humorous short story, "The Elephants on Neptune" by Mike Resnick, was published in Asimov's Science Fiction, and was nominated for both a Hugo and a Nebula award (2001). The pilot of the TV movie Virtuality centers around a starship preparing to make a flyby of Neptune before leaving the Solar System. The Star Trek: Enterprise pilot episode "Broken Bow" briefly mentions Neptune, with Jonathan Archer saying that at Warp 4.5 speed, it is possible to fly to "Neptune and back [to Earth] in six minutes." In the point and click game Anastronaut: The Moon Hopper, the player visits the planet Neptune in a future setting. In the manga and anime series Sailor Moon, one of the supporting characters is named Sailor Neptune; she is also known as Michiru Kaioh. She fights along with the other Outer Senshi for the Moon Kingdom and protect the Solar System from outside enemies. She carries a talisman known as Deep Aqua Mirror and her powers are based in deep water. In the cartoon series Futurama, the character Robot Santa Claus has his heavily fortified home base on the north pole of Neptune. In The Fairly OddParents episode "Wishology! Part 3: The Final Ending," Poof went to Neptune to make a magic wand. The Doctor Who episode "Sleep No More" is set on a space station orbiting Neptune. In the Hyperdimension Neptunia video game series, Neptune is the goddess of the nation known as Planeptune. The French comics Les Fantômes de Neptune (2015), by Valp is a steampunk adventure. The stories begin on Europa, a moon of Jupiter, and continue on Neptune.

Last and First Men: A Story of the Near and Far Future is a "future history" science fiction novel written in 1930 by the British author Olaf Stapledon. A work of unprecedented scale in the genre, it describes the history of humanity from the present onwards across two billion years and eighteen distinct human species, of which our own is the first. The book employs a narrative conceit that, under subtle inspiration, the novelist has unknowingly been dictated a channelled text from the last human species.

Mothstorm is a young adult novel by Philip Reeve and released in October 2008. Illustrated by David Wyatt, it is the third book in the Larklight Trilogy, sequel to the 2007 novel Starcross.

Nearly Neptune is a juvenile science fiction novel by British writer Hugh Walters, the twelfth in his Chris Godfrey of U.N.E.X.A. series. It was published in the UK by Faber in 1969 and in the US by Washburn Books under the title Neptune One is Missing.
Ricky Ricotta's Mighty Robot is a series of children's graphic novels written by Dav Pilkey and first seven books illustrated by Martin Ontiveros and all nine books, including two long-awaited sequels, illustrated by Dan Santat. In each book, Ricky Ricotta, a mouse, with the help of his mighty robot, saves the world from an evil villain. Also, the books each have an alien creature from a different planet in order from closest-to-sun to farthest-from-sun including Earth, as the villain of the first book is from Earth. The reader could see the villains being jailed in each series and later notice the familiar villains from previous books.

Sailor Neptune is a fictional lead character in the Sailor Moon media franchise. Her alternate identity is Michiru Kaiou , a teenage Japanese schoolgirl. Michiru is a member of the Sailor Soldiers, female supernatural fighters who protect the Solar System from evil.

The Secret of the Ninth Planet is a science-fiction novel written by Donald A. Wollheim and first published in the United States in 1959 by the John C. Winston Co. Wollheim takes his heroes on a grand tour of the Solar System as that team struggles to prevent an alien force from blowing up the Sun. This is the last of three juvenile novels that Wollheim wrote for Winston, the other two being The Secret of Saturn's Rings and The Secret of the Martian Moons.

"Sleep No More" is the ninth episode of the ninth series of the British science fiction television series Doctor Who. It was first broadcast on BBC One on 14 November 2015. It marked the first time an episode of the series had not featured any opening titles - the title and writer were instead announced at the beginning of the end credits.