It’s remarkably difficult to make a sci-fi show that’s truly and entirely flawless. After all, when you make a story meant to span the course of several seasons and dozens (or even hundreds) of episodes, there’s bound to be a dud here or there. There are some exceptional sci-fi series, however, that can brag about not having a single episode that could be considered bad.
From classics to modern gems and from animation to live-action, these are some of the best sci-fi shows ever made, as proved by the fact that all of their episodes are, at the very least, good. When even your weakest episode has a ton of things to offer, you know you’ve got a terrific show on your hands. These series are ranked according to the quality of their worst episode.
1
‘Cowboy Bebop’ (1998–1999)
One of the most groundbreaking sci-fi shows in history, the cyberpunk masterpiece Cowboy Bebop follows the futuristic adventures and misadventures of a bounty hunter and his partners. It’s anime storytelling at its very best, mixing elements of genres like the Western and noir with themes of existentialism and struggling with the past.
Though it only ran for 26 episodes, this iconic sci-fi show was a tremendous hit both in Japan and the West, and remains one of the most beloved series of its kind. The weakest episode is usually agreed to be “Boogie Woogie Feng Shui”—which, admittedly, kills a lot of narrative momentum. Nevertheless, it’s not a bad episode by any measure, proving why this is one of the best TV masterpieces of the last 30 years.
2
‘Invincible’ (2021–)
Another great animated sci-fi show, Invincible is a superhero series created by Robert Kirkman, based on his own comic book series. It follows the life of a superpowered teenager whose father is the most powerful superhero on the planet, and throughout its run, it has served as one of the freshest and most unique superhero shows out there.
Full of gravitas, pathos, and great character writing, Invincible is an amazing show first and a great superhero story second. When your show’s worst episode is something as funny and visually inventive as“In About Six Hours, I Lose My Virginity to a Fish”, you know you have one of the best superhero shows of the last five years on your hands.
3
‘Severance’ (2022–)
Apple joined the streaming game relatively recently, but since then, Apple TV+ has been putting out some of the best sci-fi shows the small screen has seen in years. Chief among them is Severance, the story of a team of office workers whose memories have been surgically divided between their work and personal lives.
Severance isn’t just amazing: It’s one of those rare shows that have literally not a single bad episode. “Sweet Vitriol” is an easy pick for the series’ worst 37 minutes, but even that has a powerful gloomy atmosphere and a great Patricia Arquette performance, which prevents it from even coming close to being bad. This is one of the most consistent shows the genre has seen in some time, and fans can only hope it remains that way.
4
‘The Expanse’ (2015–2022)
Praised as one of the most scientifically accurate sci-fi shows ever, The Expanse started out as a slow-burning space opera on Syfy, where it was tragically canceled after three seasons. Thankfully, Amazon saw the potential in the show and picked it up for another three seasons. Now, here we have one of the greatest science fiction stories the small screen has seen this century, about a team unraveling a conspiracy after the disappearance of a rich-girl-turned-political-activist.
The Expanse is one of the best shows set in space, a complex masterpiece with a tremendous sense of scale and some incredible writing. It’s not often that a sci-fi series with these many seasons and episodes manages to go without a single true miss, yet The Expanse‘s weakest episode is probably the pilot, “Dulcinea,” and that’s one of the best pilots of any 21st-century sci-fi show. Make of that what you will.
5
‘The Leftovers’ (2014–2017)
The sci-fi elements in The Leftovers, one of the best HBO original shows ever, are relatively subtle, but this is undeniably a genre series. Who said that prestige television couldn’t delve into sci-fi, too? This is the story of a group of people in a small New York community who try to continue their lives after the disappearance of 2% of the global human population.
Each of The Leftovers‘ three seasons are among the highest-rated seasons of television on IMDb, which makes it no surprise that it has such an abundance of exceptional episodes—and a complete absence of bad ones. The show’s worst episode is probably something like “Penguin One, Us Zero” or “B.J. and the A.C.”, and those are pretty solid early episodes in the series’ first season; so there’s nothing much to complain about here.
6
‘Andor’ (2022–2025)
Absolutely no one was expecting a spin-off/prequel show based on a semi-popular character who was created for a Star Wars spin-off to end up becoming the star of a show that’s the best the franchise has been since 1980. Andor is a triumph, jumping between chapters in Cassian Andor’s (Diego Luna) journey toward Rebel heroism during an era filled with danger, deception, and intrigue.
It’s probably the first season’s first episodes, “Kassa” and “That Would Be Me”, that tend to be considered the weakest of the bunch.
The fact that so many of Andor‘s episodes can be called masterpieces is admirable, and the fact that none of them are genuinely bad is just as well. It’s probably the first season’s first episodes, “Kassa” and “That Would Be Me”, that tend to be considered the weakest of the bunch, yet even those are praised for their engrossing set-up of Cassian and his arc.
7
‘Counterpart’ (2017–2019)
One of the most criminally underrated sci-fi shows ever, Counterpart is a masterful thriller with J.K. Simmons at the top of his game in the lead. In it, a cog in a bureaucratic agency discovers his organization is guarding a crossing to a parallel dimension. The result is a slow-burning yet engrossing tale with some surprisingly nuanced lore; one which was canceled well before its time.
If Counterpart had been allowed to continue like it should have, perhaps it would have run into a roadblock at some point. The way things are today, though, the series’ weakest entry is probably Season 1’s “Birds of a Feather” or the intro to Season 2, “Inside Out.” The thing is that in no way are those episodes anything less than riveting pieces of sci-fi thriller television that, in any lesser show, might be considered among the show’s best episodes.
8
‘Watchmen’ (2019)
Alan Moore‘s Watchmen comic book limited series is one of the most important works in the history of the medium, so any adaptation of such a seminal work of fiction should live up to its standards. Thankfully, HBO went above and beyond with their Watchmen. Divisive though it may be, many would dare call it one of the best sci-fi miniseries of all time. It’s set in an alternate history, one where masked vigilantes are treated as outlaws.
With a standout cast, lots of interesting twists on the source material, and lots of compelling sociopolitical themes, Watchmen is one of the defining science fiction series of the 2010s. Of course, in a show that only has nine episodes, it’s much easier to have zero bad ones; but even Watchmen‘s weakest, which is probably “Martial Feats of Comanche Horsemanship”, is so great that praise is in order.
9
‘Dark’ (2017–2020)
Netflix’s first-ever German-language series, Dark became a surprising cult classic that perhaps not even the streaming giant saw coming. Proof that sci-fi slow-burns are always worth it, Dark explores a family saga with a supernatural twist, set in a German town where the disappearance of two young children exposes the relationships between four families.
Dark is deliberately mind-bending, and occasionally so challenging to follow that it demands the viewer keep a notebook at hand at all times. It’s so well written and so impeccably directed, however, that one is constantly motivated to try and keep up. The show’s weakest entry might be its pilot, “Geheimnisse”, but even that’s a stretch. Nearly all of Dark‘s episodes are as close as sci-fi television comes to a 10/10 across the board.
10
‘Firefly’ (2002–2003)
Probably best known for having been tragically canceled after only one season, Firefly is by far one of the most iconic sci-fi series of the 21st century. Aided by a thrilling space Western tone, some great production values, and one of the best casts in the history of sci-fi TV, it follows a renegade crew aboard a small spacecraft as they try to survive the unknown parts of the galaxy.
Firefly is irresistible, full of compelling character arcs, exciting storylines, and unforgettable episodes. Even the series’ lowest-rated episode on IMDb, “Safe,” has an admirable rating of 8.0. There are plenty of sci-fi shows whose best episode doesn’t even come close. Firefly, then, is far more than just a beloved cult classic: It’s a transcendental piece of sci-fi storytelling that’s not likely to get old anytime soon.
Firefly
- Release Date
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2002 – 2002
- Network
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FOX
