Science fiction is a notoriously diverse genre harboring some of the most dedicated support bases in all of fandom. With that in mind, it is impossible to please everyone when creating a list of the best of all time. Depending on who you ask, anything from the MCU to the Transformers series could be dubbed sci-fi. So, take this definition loosely. In the interest of best representing, said diversity franchises will be represented by a single film and ranked among the 20 best sci-fi films of all time.

Updated: November 2022: To keep this article fresh and relevant by adding more information and entries, this article has been updated by Wishka Tilakaratne.

20 Cube (1997)

Cube by Vincenzo Natali
Trimark Pictures

This 1997 flick is not the highest-quality entry on this list, but it is a significant addition to both the sci-fi and horror genres. Cube's authoritarian take on futuristic crime and punishment has seen the film enjoy a cult following to this day, and the trap-based horror elements have spawned a sub-genre of its own. It's even more impressive considering Cube was an independent feature made on an estimated budget of just $350,000.

19 Predator (1987)

The predator, an alien
20th Century Fox

Sticking with the horror theme, Predator is almost faultless in the narrative it's trying to tell. The titular monster has remained a pop culture icon, spawning multiple sequels, although none came close to capturing the magic of the original. The over-inflated macho tone lends perfectly to the cast's talents, and pitting man vs alien in a battle to the death remains a simple but very effective concept.

Related: Every Movie in the Predator Franchise, Ranked

18 Forbidden Planet (1956)

Forbidden Planet 1956
Metro-Goldwyn-Mayer

A progenitor of the sci-fi genre and the first major attempt to push science fiction out of the B movie scene, it was firmly entrenched in. Sadly underappreciated in its time, the flop set back the career of comedic icon Leslie Nielson significantly, but thankfully time has seen Forbidden Planet elevated to cult status. An adaptation of Shakespeare's The Tempest, it's pulp fiction at its finest and the genre as we know it today simply couldn't exist without this one bold step.

17 Star Wars: A New Hope (1977)

Han Solo, Princess Leia Organa and Luke Skywalker
20th Century Studios

Controversially low entry for arguably the most popular sci-fi series of all time, but it's a series that at this point has had at least as many misses as hits. Highlighting the original as the pick of the bunch because, like Forbidden Planet, it's impossible to understate the significance the film has had on the genre as a whole. In Star Wars: Episode IV - A New Hope, George Lucas finally perfected the art of bringing science fiction to a mainstream audience, and cinema is all the better for it.

16 2001: A Space Odyssey (1968)

Keira Dullea as Dave Bowman, the protagonist
MGM

Another classic pioneer, legendary filmmaker Stanley Kubrik excelled at every genre he put his hand to and produced numerous well-regarded classics in his time. 2001: A Space Odyssey broke ground for visual spectacle in cinema and was truly awe-inspiring upon its release, like nothing that came before it. It also has the honor of being the only film from the acclaimed director to receive the Academy Award.

Related: These Are the 7 Best Stanley Kubrick Films, Ranked

15 Her (2013)

Joaquin Phoenix as Theodore Twombly
Warner Bros. Pictures

Spike Jonze's twisted romantic feature is far from the high-concept sci-fi of a lot of other films on this list. But the question of a lonely man falling in love with an artificial intelligence program is a poignant and increasingly relevant moral exploration. Her is another remarkable entry from the quirky filmmaker, and Joaquin Phoenix is at his enigmatic and emotionally fraught best in the lead.

14 12 Monkeys (1995)

Bruce Willis as James Cole in 12 Monkeys
Universal Pictures

Mind-bending in a different way, Monty Python alum Terry Gilliam peaked with the '90s time travel classic, 12 Monkeys. Taking a drab look into a post-apocalyptic future and focusing on elements of penal reform, convict James Cole is sent back in time to prevent the outbreak of a deadly virus that nearly ended all life on earth. The problem being when he arrives in the past to complete his mission everybody assumes he's crazy, and the film plays with the audience's conception of what's real and what isn't throughout.

13 Minority Report (2002)

Tom Cruise as Chief John Anderton, Precrime program commanding officer
20th Century Fox

Phillip K. Dick is arguably the definitive name in dystopian science fiction, and it won't be the last time an adaptation of his work appears on this list. Another film that seeks to tackle futuristic crime and punishment, Minority Report imagines a world where people can be arrested before committing crimes to create a utopian society where crime never starts. The filmmakers did a ton of research into where technology was predicted to be by 2054, and watching some of those dystopian predictions come true, makes it a hauntingly plausible future.

12 The Terminator (1984)

Arnold Schwarzenegger as the Terminator
Orion Pictures

An often-quoted classic with a slew of sequels that fail to live up to the standards set by the first two entries. In a post-apocalyptic future where machines have taken over, a killbot is sent back in time to eliminate the leader of the human resistance, so they can end life once and for all. A fantastic premise with a great movie to match, but unnecessary sequels diluted this premise and weakened the series as a whole. There's money to be made, but a little creative integrity would have helped The Terminator endure as a fantastic two-part saga.

11 Back to the Future (1989)

Marty McFly with Doc
Universal Pictures

Probably the campiest entry on the list, but a timeless classic nonetheless, and it's hard to overlook the fantastic time travel trilogy. Everybody has at some point in their life seen Back to The Future and it fully deserves the significant following it still enjoys. Following on from the real-world year of 2015, which was depicted here with far more flying cars than we actually had, the series has also enjoyed a strong resurgence. Re-releases, merchandising and a Broadway musical, not to mention rumors of a reboot, prove Back to the Future still has plenty of appeal.

10 The Martian (2015)

Matt Damon as Dr. Mark Watney
20th Century Fox

A fantastic return to form for legendary sci-fi director Ridley Scott, based on the novel of the same name. Mark Watney finds himself stranded on Mars after a storm forces his team to evacuate the planet, presuming him dead. Watney must survive for far longer than planned, with the crew attempting a risky mission to slingshot around the earth and return for their stranded comrade. The Martian is a brutally nihilistic watch at times, and the writing hits its emotional cues expertly.

9 Moon (2009)

A scene from Moon
Sony Pictures Classics

The film that launched Duncan Jones' career set the standard impossibly high for the young filmmaker to follow, at least so far. Sweeping up promising newcomer awards, Moon dropped one of the most teasingly mysterious trailers in recent memory. Astronaut Sam Bell is close to completing a solitary mission on the moon when he comes across a stranded rover. He quickly goes to explore and discovers a man who is his exact double unconscious behind the wheel. The film's mysteries are better left unspoiled, and having the brilliant Sam Rockwell in the lead certainly doesn't hurt the film either.

8 Arrival (2016)

Amy Adams pointing at black markings in Arrival
Paramount Pictures

By branching out into the field of linguistics, Arrival focuses on the possible human interaction with extraterrestrial beings. However, rather than posing these "aliens" as monsters or creatures that focus on erasing the human race, this film tends to illustrate "what space might be able to teach us about time". Moreover, the inclusion of world politics allows the film to explore ideologies like war and peace that are very much relevant to society.

7 Interstellar (2014)

Joseph Cooper, Dr. Brand and Romilly visits an aqua planet
  • Paramount Pictures

With Matthew McConaughey taking the lead role of Joseph Cooper, who ends up being a part of a space mission by NASA, Christopher Nolan plays with time and space to bring forth this phenomenal film. Interstellar focuses on a dystopian futuristic Earth where the planet is starting to become toxic for the human race. The film is quite emotional but also leaves much to think about. With the current climate change crisis, Interstellar might be very relevant even today.

6 Inception (2010)

Arthur fighting against a character in the dream.
Warner Bros. 

Yet another Nolan film that received high rates and critical success, Inception has all the ingredients necessary to leave the viewer shocked. With an unexplainable ending, the film focuses on the architecture of the human mind and the ability to control it via dreams. The film went on to become the fourth highest-grossing film of 2010. Of course, the leading role being played by Leonardo DiCaprio alongside Joseph Gordon-Levitt and Elliot Page is a huge plus point.

5 Ex-Machina (2015)

Alicia Vikander as Ava, an artificial intelligence and android
A24

A morally ambiguous exploration of artificial intelligence that could serve as a very prominent discussion point in the future if and when we broach these boundaries in real life. Ex Machina essentially ponders at what point machines become 'human' and by extension whether they then deserve human rights. It's a quandary real-world scientists are already discussing, and Ex-Machina is a fascinating depiction of it at work, a must-watch.

4 Blade Runner (1982)

Harrison Ford as Rick Deckard from Blade Runner
Warner Bros.

Whenever discussing the greatest sci-fi films of all time, Blade Runner is a name that inevitably gets brought up. Another Phillip K Dick adaptation and another entry for Ridley Scott. For many, it's the definitive example of dystopian fiction, and its gritty, neon-soaked aesthetic is certainly one that has been ironically replicated again and again.

3 The Matrix (1999)

Carrie-Anne Moss as Trinity and Keanu Reeves as Neo
Warner Bros.

With its sophisticated visual effects and brilliant performances by the cast, The Matrix is a cult classic that is still being talked about. This 1999 movie focuses on the idea of technology overpowering humanity. Through the blend between the facade and what is real vs. unreal, this particular film by Lana and Lilly Wachowski ensures that the viewers are left confused but excited. The complex nature of the film has allowed it to be opened to many interpretations. In fact, Lilly Wachowski told during an interview in 2020 that the film was a "trans metaphor" and "that was the original intention, but the world wasn't quite ready".

Related: How The Matrix: Resurrections Tackles Toxic Nostalgia and Reboots

2 Alien (1979)

Ripley scared of the alien
20th Century Fox

The sense of dread imparted on the crew of the Nostromo after they unknowingly pick up a hostile alien species makes for one of the all-time greats of the sci-fi and horror genres. The subsequent sequels, while again not quite matching the success of the original, have made the Alien series the highest-grossing horror franchise ever. And the titular Xenomorph has become a sighting so iconic it transcends the franchise itself. Blade Runner remains a fan favorite, but Alien was Ridley Scott at his sci-fi peak.

1 The Thing (1982)

Russell in The Thing
Universal Pictures

Another peak for another legendary director, John Carpenter's The Thing owes almost as much to Alien as it does to the 1951 pulp sci-fi classic that inspired it. But adding in the paranoia factor of a shapeshifting alien that could be anyone hiding in plain sight ratchets the suspense even higher. The Thing is also unafraid to let the nihilism hang with the situation never really increasing beyond hopelessness. It's perfect in its execution and warrants its place among the best sci-fi films of all time.