Most people don’t think of Star Trek as a horror franchise. They think of it as optimistic science fiction, full of diplomacy, exploration, and the belief that humanity will eventually figure things out. That reputation is largely deserved, but almost entirely incomplete. Across nearly 1,000 television episodes spanning 60 years, the franchise has produced some of the most genuinely terrifying hours in science fiction television history. Here are the best of them.
10. ‘Wolf in the Fold’ — The Original Series, Season 2
Written by Robert Bloch, the author whose 1959 novel PsychoAlfred Hitchcock adapted for the screen, this episode follows Scotty as he becomes the prime suspect in a series of murders on a pleasure planet. The real culprit is an incorporeal entity that feeds on fear and one that, the episode eventually reveals, was also Jack the Ripper. It’s been called the ‘scariest episode of the original series’ with a Gothic atmosphere that holds up across six decades.
9. ‘Catspaw’ — The Original Series, Season 2
Another Bloch-penned entry, this one leaning directly into Halloween iconography: black cats, skeletons, witches, a haunted castle on an alien planet. It’s campy by modern standards, but it remains the original series’ most overt attempt to make the audience genuinely uncomfortable.
8. ‘Genesis’ — The Next Generation, Season 7
A pathogen spreads through the Enterprise crew and begins de-evolving the crew members into their prehistoric ancestors. Worf transforms into a spined, Predator-like creature. Picard de-evolves into a primate. Data is unaffected and must save the ship alone. MovieWeb ranks it among the most ‘disturbing Trek episodes ever‘, and the image of a fully de-evolved Worf stalking the corridors is hard to shake.
7. ‘Conspiracy’ — The Next Generation, Season 1
Picard discovers that parasitic alien creatures have infiltrated the upper ranks of Starfleet, taking control of commanding officers from the inside. The episode climaxes in a scene that remains, to this day, perhaps the single most graphically violent moment in franchise history. It’s been called a genuine piece of Cronenbergian body horror.
6. ‘Empok Nor’ — Deep Space Nine, Season 5
Written by future Hannibalshowrunner Bryan Fuller, this episode strands Miles O’Brien and a salvage team on an abandoned Cardassian space station that is very much not empty. SlashFilm calls it Trek’s purest execution of the haunted house format, a self-contained slasher episode that functions as a miniature horror film.
5. ‘The Thaw’ — Voyager, Season 2
The Voyager crew discovers colonists in artificial hibernation, trapped inside a computer-generated environment controlled by a single entity: Fear itself, manifested as a malevolent electronic clown played by Michael McKean. It is one of the stranger hours in franchise history and one of the most unsettling.
4. ‘All Those Who Wander’ — Strange New Worlds, Season 1 |
The newest entry on this list and among the most deliberately frightening. The Enterprise crew investigates a crashed ship and discovers Gorn hatchlings which, in Strange New Worlds, are not the lumbering lizard men of the original series but fast, vicious, chest-bursting predators that drew directly from Alien, Ridley Scott’s horror template and made no effort to hide it. It worked.
Related: Star Trek Legend Weighs in on AI: ‘Evolve or Die’
3. ‘Schisms’ — The Next Generation, Season 6
Crew members on the Enterprise begin suffering sleep deprivation and vague, unshakeable dread. Under hypnosis, they reconstruct fragmented memories of a cold metal table and alien hands working in the dark. Screen Rant calls it the single scariest episode in franchise history, and the alien abduction horror it deploys is all the more effective for how long the episode withholds showing the creatures responsible.
2. ‘Q Who’ — The Next Generation, Season 2
The first appearance of the Borg. Q launches the Enterprise into deep space and the crew encounters a species that destroys entire civilizations not out of malice but purely out of hunger. The buildup is exquisite with barren planets, stripped clean, as the crew realizes that what left them that way is an existential threat in the true sense of ‘cosmic horror.’
1. ‘Best of Both Worlds’ — The Next Generation, Seasons 3–4
Technically two episodes, and impossible to separate. The Borg return and assimilate Captain Picard, transforming him into Locutus and using him to nearly destroy Starfleet at the Battle of Wolf 359. It’s the franchise‘s greatest cliffhanger and one of the finest horror achievements in science fiction television history. The image of Patrick Stewart in Borg implants, announcing the Federation’s imminent destruction in a flat monotone, is as frightening as this franchise gets. And everyone had to wait until the next season to find out how Riker’s attempted destruction of Picard would turn out.
Which Trek episodes do you think were scariest?
This story was originally published by Parade on May 17, 2026, where it first appeared in the News section. Add Parade as a Preferred Source by clicking here.
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