There's something about the clean lines of a bob, particularly with bangs, that suggests a sci-fi setting. Despite the style dating back to the twenties (and being the defining hairstyle of the timeframe), they are still seen as a little bit rebellious and progressive. After all, Long Hair Is Feminine, so short styles can be shorthand for a more gender equal society. Additionally, the simple, straight lines fit in well with an Ascetic Aesthetic, marking the character as belonging to that timeframe. Not to mention, short hair tends to cause fewer problems with zero-g, helmets, and space suits.
Unlike its Sister Trope the Twenties Bob, Sci-Fi Bobs are almost always mathematically straight edges and hair without curls. Fashionable Asymmetry is also common, one side of the bob being longer than the other.
- Meifon Li◊, the main character and leader of a Space Pirate-fighting service from Angel Links has a short bob.
- Robot Girl, R. Dorothy Wayneright◊ from has a The Big O has a bob.
- Faye Valentine◊ from from Sci-Fi Noir series Cowboy Bebop.
- In Judge Dredd, Judge Hershey's practical bob hairstyle is her most noticeable physical trait.
- The title character◊ in the sci-fi dystopian film Æon Flux sports a short bob cut.
- Hope van Dyne◊ from Ant-Man sports the same bob cut as her late mother, Janet van Dyne AKA The Wasp, a superheroine with shrinking powers thanks to the Pym Particle and a suit. At the end of the film, it's stated that she will become the next Wasp with the updated suit her father Hank had created in secret. By the time of the next film, she's grown it out.
- Sonmi~451 and the other fabricants in the Cloud Atlas movie.
- Rookie judge Cassandra Anderson◊ sports a blond wavy bob while she's taught by Judge Dredd in Dredd how to deal with Ma-Ma's criminals in her building in Mega City One.
- The Fifth Element's Leeloo has unnaturally bright orange bobbed hair. Unusually for this trope, it's fairly messy.
- Laliari in Galaxy Quest sports a bob cut while in human form.
- Miss Namikawa in Invasion of Astro-Monster, along with every other Xilian woman.
- Big Bad Irina Spalko◊ sports this style in Indiana Jones and the Kingdom of the Crystal Skull, perhaps fittingly seeing as the film is an homage to the 50's style sci-fi b-movie.
- Sylvia Weis◊ female lead from the Sci-Fi Action/Adventure film In Time has a pageboy haircut. Her grandmother also has one.
- Claire Dearing◊ operates Jurassic World, a resort and dinosaur natural park with the highest technology, with a mandatory, though fiery, bob cut. Her clean and smooth hair gets gradually dirtier and wavy◊ as she gets more into jungle and dinosaur action.
- In the movie Notting Hill, Julia Roberts played fictional actress "Anna Scott", who wore one of these while starring in a fictional SF movie "Helix"◊.
- Mako Mori◊, female lead and Humongous Mecha pilot, from Pacific Rim has a bob cut with blue highlights.
- Friday in the 1964 film Robinson Crusoe on Mars is an uncommon male example.
- In Solo, Qi'ra's initial hairstyle is this, though it's a bit softer and messier than most examples. By the time she meets Han Solo again following a Time Skip of three years, she's grown her hair out.
- Quorra from TRON: Legacy. She combines this with Fashionable Asymmetry.
- Doctor Who Expanded Universe: Benny Summerfield, of the Doctor Who New Adventures and later her own series, started with short hair, and subsequently seems to have grown it out to about bob length.
- Several characters of both genders in the Honor Harrington series are described as having shorter hair than is strictly fashionable, ranging from a bob cut all the way to shaved heads, specifically because loose hair floating around in a zero-g and/or industrial environment can be both inconvenient and potentially dangerous. On the planet Masada, male spacers (there are no female Masadan spacers) can be easily identified by their short hair and clean-trimmed facial hair, in contrast to everyone else having long hair and beards.
- The title character in Cleopatra 2525 has a blonde bob.
- Chiana and other female Nebari from Farscape combine this with White-Skinned Space Babe. Like Leeloo, it's a bit more messy than typical for the trope, but Farscape (which takes place in the present day, only far from Earth) does have a Used Future aesthetic.
- Ridiculously Human Robot Werther from Guest from the Future is a Rare Male Example.
- Rachel on Orphan Black has a harsh bob , which differentiates her from the rest of her clones, as well as differentiates her as being seemingly the only clone working for Project DYAD.
- Red Dwarf: The AI computer Hilly (she's just a head on black screen) from "Parallel Universe" wears Sci-fi Bob Haircut. In the third season, she became a regular when the crew's computer Holly decided to take her likeness and make a gender swap. In the later episodes, however, her hair was longer.
- Star Trek:
- Many Vulcans in the Star Trek franchise wear their hair this way, including Lt. Valeris, although there are exceptions. The Vulcans are, at least initially, a much more technologically advanced race than the humans.
- Lt. Saavik defies the trope in Star Trek II: The Wrath of Khan, wearing her hair long.
Kirk: Lieutenant, are you wearing your hair differently?
Saavik: It is still regulation, Admiral.
- Bajoran officer serving on the Enterprise Ro Laren in Star Trek: The Next Generation. She has dark hair and wears a bob without bangs.
- Dr. Beverly Crusher from The Next Generation has rather long red hair most of the time, but she bobbed her hair for one season.
- Android Lal was created by Data as a blank slate, even in terms of species. Lal chose to look like a young human woman with pale complexion and black hair in a short bob with bangs.
- Carol Marcus◊ in the rebooted series, starting with Star Trek Into Darkness. She has a blonde simple bob.
- In UFO, Lt. Ellis and her compatriots in SHADO's moon base wore a purple wig as part of her uniform.
- Doctor Who:
- Zoe Heriot has this as a science-minded companion to the Second Doctor, who he met in a space station in the future.
- The Thirteenth Doctor's hair, although she doesn't have bangs and it's somewhat longer than is usual.
- Quill from Class has a very menacingly exact blonde bob. The show has a contemporary setting, but she is an alien in human disguise.
- Doctor Who:
- Cortana◊ from the Halo series is an advanced military AI whose holographic avatar tends to have bobbed hair, particularly in the original Halo: Combat Evolved.
- Maya, the Siren class from Borderlands 2, has an electric blue bob cut.
- When EDI takes control over Dr. Eva's body in Mass Effect 3 she gets a metal bob haircut (Picture spoiler for Mass Effect 3).◊ She explains that it is not "hair" in the strict sense but a memory-shape metamaterial used to simulate hair. She just prefers to gather it into a protective bob shape when not using it for anything else.
- Faith◊, the protagonist from Mirror's Edge, which takes place in a Post-Cyberpunk setting, has a black bob haircut.
- The default appearance of the RAcaseal◊ class in Phantasy Star Online is a fembot with the top portion of their heads shaped like bobbed hair.