A movie doesn't need to belong to the horror genre to be disturbing, scary, or terrifying. Sure, the most reliable genre for getting one's heart racing and nerves on edge will likely remain the horror genre, but movies don't always fit neatly into one category. This can lead to horror movies being funny, comedies feeling tense, and seemingly ordinary dramas being terrifying, to name just a few examples.

The unpredictability of it all is one of the things that makes watching new movies so exciting. To focus on one type of unexpected emotional reaction, the following movies aren't classified as horror movies (at least according to the social media/film site Letterboxd), yet may prove tense and unnerving for those who choose to watch them. For anyone wanting to experience unique feelings of terror outside the horror genre, these films are all essential viewing.

Updated on September 1, 2023, by Jeremy Urquhart:

It's interesting to look over some of the scariest non-horror movies out there, because they can offer unexpected or unique types of horror, and thereby are very capable of getting under one's skin. When it comes to the following movies, few will get labeled as titles belonging to the genre in question, though they are undeniably scary movies that aren't horror (at least not in the traditional sense). Fear's subjective, though, so there's every chance some viewers will find these to be more confronting or uncomfortable than others will.

15 'A Clockwork Orange' (1971)

Alex in his iconic suspenders outfit looking into the camera in 'A Clockwork Orange.'
Image via Warner Bros.

Stanley Kubrick would wholeheartedly embrace the horror genre in 1980 with his adaptation of The Shining, but just under a decade earlier, he made another film that presented a similar level of unease and terror. That film was 1971's A Clockwork Orange, a crime/sci-fi movie about a particularly ruthless gang of criminal youths and the drastic steps taken by the state to brainwash its leader into no longer committing crimes.

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A Clockwork Orange doesn't pull any punches when it comes to establishing its horrifying world, nor the acts its protagonist, Alex (Malcolm McDowell), is capable of committing. Similarly disturbing is the idea of being robbed of one's free will through a State-sanctioned psychological procedure, done with the pretense of preventing crime before it happens. It contains both shocking scenes and disturbing themes in spades, making it an effectively unnerving watch despite not technically being a horror movie.

14 'Neon Genesis Evangelion: The End of Evangelion' (1997)

End Of Evangelion

As a series, Neon Genesis Evangelion was pretty traumatic at times and put its main characters through numerous ordeals. The 1997 movie, The End of Evangelion, aimed to conclude the original mid-1990s series in an epic, haunting fashion, putting its characters amid a truly apocalyptic scenario. It's an all-time great anime movie, sure, but it's also far from an easy watch.

Given its ability to function from start to finish as a finale, it's a film that hits the ground running and never lets up, proving tense, unnerving, and stomach-churning for most of its runtime. It's violent, grim, and eventually surreal, capturing the end of the world and the psychological breakdown of its protagonist Shinji Ikari in unflinching detail.

Watch on Netflix

13 'The Nightingale' (2018)

A woman running through a forest with a rifle
Image via Transmission Films

Jennifer Kent is one of the most exciting Australian filmmakers working today, with her breakout success being the tense and psychologically terrifying 2014 horror film The Babadook. Her 2018 follow-up, The Nightingale, isn't definable as a horror movie, being more of a revenge thriller with a historical setting, focusing on a young Irish convict and an Aboriginal tracker who have both been the victims of violence and are seeking vengeance for their own reasons.

It might not deal with supernatural or psychological horror like The Babadook does, but if anything, The Nightingale is arguably even more difficult to watch. It goes to some incredibly dark places and refuses to shy away from the devastation caused by colonialism, making it one of the hardest-to-watch thrillers in recent memory. It's powerful and well-made, but certainly not for the faint-hearted.

Watch on Hulu

12 'Nocturnal Animals' (2016)

Nocturnal Animals

A very dark blend of psychological thriller/drama and crime, Nocturnal Animals might well be up there with the most uneasy films of the past decade or so. It's effectively two stories in one, with the initial premise following a woman receiving a manuscript from her ex-husband, and the other story being a visual depiction of the story contained within said manuscript.

The latter story is more outwardly terrifying, but the former still feels tense and uncomfortable throughout, being a dark character study and an all-around unsettling time. It's hard to put into words what makes Nocturnal Animals provoke the emotions it does, but after sitting through the movie, it's hard to deny the impact it has.

Watch on Netflix

11 'Come and See' (1985)

Elim Kilmov's Come and See (1985)
Image via Sovexportfilm

One of the main reasons Come and See is considered an all-time great war movie is because of how nightmarish it is. It depicts the physical and psychological toll of being involved in warfare, having a story about Soviet Resistance Fighters trying in vain to combat invading German soldiers, all seen through the eyes of an initially idealistic young boy.

RELATED: The Best War Movies of All Time, Ranked

It takes on the feel of a fever dream at best, and essentially the most surreal and intense nightmare you could possibly imagine at worst. This is exactly what it needs to do, however, to succeed as the kind of anti-war film it's striving to be. This all makes it an incredibly effective movie, and something that's about as scary as war movies can get, though its uncompromising nature means it won't be for everyone.

Watch on The Criterion Channel

10 'The Seventh Continent' (1989)

The Seventh Continent - 1989
Image via Wega Film

Right from the start of Michael Haneke's feature filmmaking career, he was unafraid to confront dark themes and mortifyingly distressing stories. This is established right from his first feature film, 1989's The Seventh Continent, which begins as a quiet and only slightly tense drama about a group of family members who seem to feel alienated from the world at large and are clearly struggling with something they don't want to openly discuss.

Their troubled lives become more obvious as The Seventh Continent goes on, as it slowly reveals what it's ultimately building to. Once it gets there, it's despairing and terribly sad, making this one of the most devastating non-horror movies out there. The fact it doesn't contain much violence, real horror sequences, or in-your-face thriller elements makes the underlying misery and terror more potent.

Watch on The Criterion Channel

9 'El Topo' (1970)

A man riding on horseback through the desert in El Topo (1970)
Image via ABKCO Films

Surreal horror is an ever-popular horror sub-genre, but sometimes, surrealism blended with another genre altogether is enough to produce something unnerving. This is the case for the bizarre El Topo, a violent and consistently surreal Western that fits in with a sub-genre sometimes referred to as an "Acid Western."

Through its strange, sometimes episodic narrative, El Topo presents a version of the West that's more nightmarish than just about any other. It honestly feels like something a particularly imaginative Western fan might conjure up in their mind during a horrific fever dream. Though it's not classifiable as a horror movie, its intense surrealism ensures it's more frightening than most true horror movies.

8 'The Revenant' (2015)

The Revenant Hugh Glass Staring off into the distance Cropped

Without a doubt, The Revenant is more graphically violent than the vast majority of horror movies out there. It's not shy about establishing its brutality early on, either, with one particularly grisly battle scene of sorts near the film's beginning. And then, the survival story of protagonist Hugh Glass that transpires shortly after is similarly unafraid to get graphic.

RELATED: The Best Westerns of the Past 20 Years, Ranked

It would qualify as a terrifying non-horror movie for its infamous bear attack scene alone, with it looking frighteningly realistic, as if Leonardo DiCaprio actually came close to being killed by a real-life bear. Of course, he didn't, as he was in good health to collect his (long time coming) Academy Award for the performance, but the scene - plus various other sequences in The Revenant - are undeniably visceral and terrifying on a primal level.

7 'Hard to Be a God' (2013)

Hard to Be a God - 2013 (1)
Image via Lenfilm Studio

With an almost three-hour-long runtime and a constantly distressing and grimy atmosphere, Hard to Be a God is a lot to handle. It's about as disturbing as non-horror science-fiction movies can get, being set on a desolate planet similar to Earth, only the population is stuck in their own Middle Ages and find themselves constantly exploited by more knowledgeable scientists from Earth.

90 minutes is a lot to handle when a movie's as disturbing as Hard to Be a God, but the runtime ends up about twice as long. It's hard to watch, violent, filthy-looking, and pessimistic, making it almost surprising that Letterboxd doesn't consider Hard to Be a God a film that fits within the horror genre.

Watch on Hoopla

6 '127 Hours' (2010)

James Franco in a canyon in 127 Hours
Image Via Searchlight Pictures

Survival movies don't get much more intense than the adrenaline-pumping mountain climbing 2010 movie 127 Hours. This is based on the true life story of Aron Ralston, a mountain climber who, while adventuring alone, found himself trapped in a canyon with a boulder crushing his arm, and completely unable to move himself without resorting to drastic measures.

By now, it's probably well-known what the movie's most harrowing scene is, but the build-up to that scene - and the willingness to have things feel uncomfortably grounded and believable throughout - is also scarily effective. It's the definition of a movie that's not for the faint of heart, and even those who can stomach the first 90% of the movie may want to shield their eyes during its infamous (yet undoubtedly effective) final scenes.

5 'No Country for Old Men' (2007)

No Country For Old Men tommy lee jones
Image via Paramount Pictures

Like El Topo, No Country for Old Men is a movie that takes Western (or at least neo-Western) tropes and iconography and uses them to craft something unsettling. Unlike El Topo, however, No Country for Old Men doesn't do this through surrealism, instead creating a tense and unnerving viewing experience through its relentless lead villain, shocking violence, pessimistic story, and an almost complete lack of music.

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It might well be the darkest movie the Coen Brothers have ever directed, with a lead villain in Javier Bardem's Anton Chigurh, one of the most menacing in recent film history. Without a villain like him, No Country for Old Men might still be a tense watch, but with him, it becomes something close to nightmarish, given the character's indifference and seeming inability to be stopped.

Watch on Prime Video

4 'Blue Velvet' (1986)

Dennis Hopper - Blue Velvet

David Lynch is a master of putting nightmarish imagery on-screen and has made films that are classifiable as horror movies (like 1977's Eraserhead and 2006's Inland Empire). Blue Velvet, however, is more of a crime/psychological thriller film and follows a young man (Kyle MacLachlan) who gets wrapped up in a wild plot with a terrifyingly deranged criminal (played by Dennis Hopper) at its center.

Hopper's Frank Booth is more frightening than just about any other movie antagonist, including those who are associated with the horror genre. Whenever he's on-screen, Blue Velvet becomes terrifying and even hard to watch, making it arguably Lynch's tensest film that doesn't fit within the horror genre.

Watch on Max

3 'Cats' (2019)

close-up of Taylor Swift in Cats
Image via Universal Pictures

The only thing more daunting than watching 2019's Cats would have been trying to work out how to market such a strange and oftentimes unpleasant fever dream of a movie. It's a (sort of) live-action film adaptation of the famous stage musical of the same name, and it's largely plotless, with most of the movie being made up of various cats introducing themselves through musical numbers.

The tone's strange, the visuals are stomach-churning to look at sometimes, and it's all just so misguided that it becomes unintentional nightmare fuel. Watching it, you get the sense that the film was supposed to be anything but a horror movie, yet the way it was ultimately put together makes it surprisingly scary, and easily one of the most uncomfortable-feeling movies of its decade.

Watch on Max

2 'In Cold Blood' (1967)

In Cold Blood - 1967

In Cold Blood takes a horrifying true-crime story and presents it in the format of a film in a totally uncompromising way. It deals with the manhunt for — and eventual trial of — a pair of murderers who killed an entire family after a botched robbery and the questions around law, order, and justice that arise from the whole sad story.

It's based on the novel of the same name by Truman Capote, which was released only one year before the film was made. It's a tough, stomach-churning watch, and it holds up as a compelling yet difficult crime film to this day, largely thanks to the way it explores its difficult themes and the fact that it does justice to the traumatic story it's based on and the people involved in it.

1 'Threads' (1984)

Threads - 1984
Image via BBC

When it comes to nuclear war, any depiction of it will likely be terrifying to some extent. It's a form of conflict that would likely end the entire world, should it occur on a large enough scale, and this is precisely a nightmare that comes true in the classic feel-bad masterpiece, Threads. It could make for a great (albeit very distressing) double feature with Christopher Nolan's Oppenheimer; that's for sure.

It's a film that still feels shocking and visceral to this day, showing life in Britain right before, during, and after a series of nuclear attacks that devastated the country and the entire world. It's a movie that deals with an alarmingly plausible apocalypse and captures everything with stark detail and a sense of realism that makes it incredibly hard to watch.

Watch on Shudder

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