Sometimes people just fail to develop into social or intellectual maturity. Maybe it's due to a very loving but confining mother or father, who don't suggest or won't let them get a job and move out, enabling their laziness or dependence instead. Maybe they were never taught any responsibility growing up, and now that they're adults, it's too late and they're set in their ways. Maybe they're a Spoiled Brat who's learned to manipulate their parents into doing what they want, and the parents came to the conclusion that it's just easier to indulge them than to fight about it. Or maybe they just didn't want to leave the nest. Maybe they've been intentionally secluded from learning about the world. Or they grew up as a neglected orphan without a proper education or any guidance towards adult life. Maybe their parents or legal guardians simply failed to teach them how to do things like cook for themselves, keep their home clean, balance the checkbook, make and stick to a budget, pay bills and taxes, do minor home repairs, or change a tire. Maybe they were literally Raised by Wolves. Maybe it's the result of brain damage, an intellectual disability or developmental disorder, or something sinister. Perhaps they just never had a life-changing moment involving a shotgun and a beloved pet. Maybe it's just a form of Mars and Venus Gender Contrast, or they live in a society with certain gender roles, where one sex is expected to be the responsible one, and the other is not expected to be (and is not always taught to be). Who can say?
Although the causes might not be clear, the effects are. The Man-Child, a term invented by William Faulkner, is usually an adult who possesses a very childlike or (stereotypically) childish demeanor. He's emotionally both simple and fragile; he prefers (although does not always need) to have a parent figure to look after him. He usually isn't very worldly and is typically pretty gullible. The Man-Child's interests are usually what most people consider to be immature or childish, sometimes even in comparison to actual children.
The character is almost Always Male. This is (presumably) to contrast the differences between him and "normal men" with the normal responsibilities and wisdom of adulthood. The female version is usually split between The Ingenue, the Genki Girl, or other tropes which highlight an adult woman's child-like attributes rather than her grown-up persona. Manchild has many more negative connotations than The Ingenue; the manchild's immaturity and lack of outward adult behavior is emphasized as being a bad thing versus being an emphasized good thing like The Ingenue's purity and idealism. This is also because of the Double Standard most societies have, which exist for various reasons, where they expect more from men than they do from women. More contemporary works are increasingly likely to play female examples as unsympathetic (or, at the very least, deeply flawed), with a characterization that is fairly similar - irresponsible, unreliable, unable or unwilling to meet basic adult responsibilities on their own, and dependent on others. When portrayed unsympathetically, female examples are typically more dysfunctional than male examples, as their parasitism is typically aimed at partners (usually viewing them as meal tickets and lifestyle subsidizers, and often cheating on them when they grow bored with them or find a better provider), and they also tend to have more severe mental health issues and are more likely to have serious issues with substances.
On the Brain Chain, the Man Child occupies a space between The Cloud Cuckoolander and The Ditz, but without necessarily becoming The Fool. He usually does not have The Fool's luck, but he doesn't necessarily play the role of the Butt-Monkey either. Although the Man-Child is commonly portrayed as being mentally challenged, he does not necessarily have to be. In many cases, the character may be very intelligent, and even leave the idealism aside and be very shrewd in business or career, but this only makes him seem creepy when others find out his emotional immaturity. Alternatively, his childlike qualities/way of thinking, when intelligently applied, can be a basis for his success as a businessman, in which case he's also The Wonka.
In comedic works, he usually plays the role of The Ditz. In dramatic works, he could be the Jerk with a Heart of Gold due to his simplicity or immaturity, or the sympathetic character we come to love. Sometimes the Man Child embarks on a late-in-the-day Coming of Age Story, which ushers him into true adulthood. Note that usually Sex as Rite-of-Passage works only some of the time. In many instances, a Man Child is not necessarily a virgin, but only sees sex as a tool of pleasure and does not recognize its emotional significance. If he ever gets married, it's likely that his wife will end up being a mother-figure not only to their children but to him as well, doing all the "emotional labor" needed to keep the household afloat while he just coasts along and drags her into all sorts of wacky hijinks. If he doesn't, there's a good chance that he's a Glorified Sperm Donor - he very likely knocked up an ex or casual sex partner, but plays no role in the child's life whatsoever, either because he can't or because he won't (quite often both).
Some will agree that this is Truth in Television for certain people, as there do exist many immature adults out there who refuse to grow up. Sometimes it's just people who are capable of engaging in adult responsibilities but have childlike interests and personalities in their free time, other times it's adults who somehow have all the knowledge capable of living independently yet the emotional maturity and mentality of a spoiled child (or teenager). The likeliest cause of the man-child is a sheltered upbringing or mental illness, particularly Peter Pan Syndrome.
One of the Kids is related, in where their childishness is caused by spending a lot of time around children. When events will force him to be independent, he will be Not Used to Freedom.
Does not relate to Never Grew Up, because they physically did grow up - but never outgrew being attached to immature or childish things or behavior. Sister Trope (perhaps) to Adults Dressed as Children, although that trope is almost always played for laughs or borders on the grotesque. Compare Keet, One of the Kids, Kiddie Kid. For a villainous version, see Psychopathic Manchild. Compare Basement-Dweller. Not related to Manchild, the British TV series, either. Compare and contrast The Three Faces of Adam. Contrast with Wise Beyond Their Years, where a child acts like an adult. Can overlap with Only One Finds It Fun for when the manchild is entertained by children's entertainment that fails to entertain the actual children.
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- Live-Action TV
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- Western Animation
- In Boonie Bears, despite being a grown adult, Bramble - the younger of the two bear brothers - acts naive and childish and is easily distracted by food.
- Abraxas (Hrodvitnon): Zig-Zagged by San, true to his rather childlike behavior among Ghidorah's three heads in Godzilla: King of the Monsters (2019). He's genuinely inquisitive and can often be very childlike even though he's an eons-old former piece of a Draconic Abomination, but besides being cute, this also highlights San's Dark and Troubled Past of being abused and starved of affection by his brothers (Ghidorah's other two heads) for billions of years. On the other hand, when San isn't being playful and childlike, he's very much capable of being serious and responsible.
- Serizawa in the Mob Psycho 100 fanfic Man Child He doesn't have the first clue how to take care of himself after breaking free from Claw...or so it seems. It's revealed later on that this has all been an act to get closer to Reigen.
- A downplayed example in A Growing Affection with Naruto. Most evident when he's giddy at the prospect of building sand castles despite being 16 and a competant shinobi. Painfully justified since Naruto's painful and lonely past as a result of being the jinchuuriki means that he never got to experience such simple pleasures of childhood. After Ino actually asks him why he's excited, he does remind her of this, causing her to promptly shut up.
- In Ace Combat: The Equestrian War Cloud Kicker, one of main heroines, has a very childish personality most of the time.
- In Batshark, a Fusion Fic combining a cartoon crossover with Batman, Elliot the deer plays Two-Face as a half-adult-half-manchild as opposed to a half-lawyer-half-criminal. And then there is the fusion of The Joker and The Warden...
- In Death's Design, Fate's Plan Hermione referred to Sirius as a "man child without the ability to grow up." Sirius replied that Harry's mother once said something very similar to him and Remus commented that every female he knew had said something similar at one time or another.
- In Friday Night Funkin' HD, Boyfriend is 19-years-old, yet he still has fun visiting a Mall Santa.
- Guys Being Dudes: Arlo is in his 20s and has the personality of an Emo Teen as well as enjoying making innuendos a bit too much. Spark acknowledges it, deciding that he, being a Transgender man, "couldn't be a preteen boy when he was a preteen, so he's making up for lost time".
- Likewise, in The Life of the Legendaries, Legendaries Mew and Jirachi are extremely immature and have many, many childish habits.
- The Grand Ruler from My Brave Pony: Starfleet Magic. He likes to play hopscotch.
- In The Last Casualties Voldemort put Harry's parents into suspended animation in a pocket dimension for thirteen years instead of killing them outright. Lily called James a man child in exasperated affection when he gave Snape a "welcome back present" by turning his robe pink.
- In a bit of Fridge Logic, James and Lily were both only 21 when they would've been killed and given how Fred and George are, the comment does not have the same effect. J.K. Rowling herself admitted she actually didn't realize how young the Potters were until much later.
- In Poké Wars, Mew is depicted as being incredibly immature. As evidenced by his words upon meeting Latias.
Mew: Hi. I'm Mew. Wanna play?
- In The Power of the Mind Remus referred to Sirius as "special" while apologizing for his behavior to a Muggle salesclerk. Harry later asked if there was any truth to that because Sirius was the biggest man child he'd ever met.
- Beelzebub from Sonic X: Dark Chaos is an immature drug-fueled hedonist that would easily be the poster for a man child if he wasn't also incredibly dangerous.
- Dragon Ball Abridged portrays Nappa as this. In this story, he is a borderline disabled Psychopathic Manchild whose dialogue mainly consists of non-sequiturs and random annoyances to his partner Vegeta to the point that "Goddammit, Nappa!" has become his Catchphrase.
- Pacific: World War II U.S. Navy Shipgirls has Chester, who treats other peoples' weapons like toys and throws them around without second thought, not to mention acting childish even during the middle of combat.
- The Tyrant and the Hero has Black Alice, who wears a "dress that wouldn’t have looked out of place on someone ten years younger" and owns a teddy bear. The plot is kicked off by her mother sending her on a journey around the world in order to gain some maturity.
- In Danny Phantom fanfic ResurrectedMemories: Ember is one of these. Despite having been a ghost for 30 years, she has not grown passed her rebellious teenage mentality.
- Children of Remnant: Weiss was hit with the Darkness the most of her siblings, and it caused her personality to regress to that of a young child. "Nice Weiss" specifically exists so that she can be more responsible when absolutely necessary.
- C Listers: Killer Moth is basically a little kid trying to be a super villain and live out his childish fantasies of being "the anti-Batman", and he constantly whines about no one taking him seriously. As more of his darker side becomes apparent, he starts to border on being a Psychopathic Manchild, but he's ultimately too much of a moron to make the leap.
- Adrien in Spellbound (Lilafly) is a teenager but gets easily excited about kindness, birthday parties, cake, and making friends. Partially because he's been socially isolated from just about everyone except his brother Félix and their friend Chloe, and partially because he's half faerie.
- Frayed Edges: Ennard acts like an innocent child, with a curious fascination for even the most mundane of things and an often simplistic sense of the world. It is deconstructed, as for all intents Ennard is a child who was kept isolated their entire life, with only their fellow animatronics and their abusive creator William Afton for company.
- War of Remnant: A RWBY Anthology: Oobleck can be rather immature for a teacher, when he realized Cinder’s team was Team CMEN was pronounced Caiman, he was about to point out he thought it was pronounced some other way before Port interrupted him.
- British lad-mag Loaded was predicated on this trope and serviced the needs of Man-Children who were beginning to feel marginalized and scorned by a society and culture that no longer valued them as much. At its peak in The '90s it had a circulation approaching half a million and spawned many imitators, including American equivalents like GQ and Maxim.
- Ringo Starr's persona in The Beatles. They generally gave him rather sweet, childish songs to sing, like "With a Little Help From My Friends", "Yellow Submarine", and "Octopus's Garden" (which he wrote himself).
- Blink182's "What's My Age Again?" is about a 23-year old who is about to get laid, but he gets distracted by the TV, so the girl leaves, and he prank calls her mother in retaliation.
- David Bowie's song "Uncle Arthur" whose protagonist runs a shop but demonstrates all the properties of a manchild.
- Devin Millar takes this up not to eleven, but 12. He dresses like a young girl with skirts and bows, has a girlish hairdo, and uses childish vocabulary. His animated characters also dress this way from the girls to even the boys.
- Buckethead, the stage persona of musician Brian Carroll, is generally built around being both childish and a little creepy. It's common for Buckethead to play with toys and trade them with the audience during his live performances. He'll also avoid talking or giving interviews in general, except in a few recorded ones where he uses his scary mask / puppet Herbie to "speak for him".
- Counting Crows' "Round Here", is about not having a conception of what being an adult means, "Round here we're never sent to bed early, no one makes us wait. Round here we stay up very, very, very, very late"
- The Idle Race's "I Like My Toys", which deals with a thirty-one year old man's desire to play with his childhood toys instead of looking for a job, much to his parents' chagrin.
- The late Michael Jackson is often said to be one. As a child, he was unable to participate in normal childhood activities due to having a demanding Stage Dad. As an adult, he engaged in childish pursuits like building a personal amusement park in his home, Neverland Ranch (whose name also connotes this trope). His song "Childhood" illustrates his struggles.
- In Barry Louis Polisar's "I Don't Wanna go to School", Tommy hides under his covers, whines and pouts to his mother about not wanting to go to school, even though he's the Principal. His mother understandably tells him to grow up.
Only little boys and girls
Ever act like you do
- In the movie The Wall, it's implied that Old Pink is one. For example, when a girl seduces him in his hotel room, he responds by trashing up the place; in "The Thin Ice" he's seen watching a Tom and Jerry cartoon on the TV; and, in "Is There Anybody Out There?" when he's building a mandala/replica of a military barracks/whatever it's supposed to be, a battery-powered toy robot is visible among the props.
- Weezer's song "Dreamin'".
- Jonathan Richman poses as one to boast his innocent songs.
- "Manchild" by Eels from their album Beautiful Freak about his sister who committed suicide in a mental institution.
- Joni Mitchell's song "A Strange Boy" from the album Hejira is about a lover who shares some man child traits:
What a strange boy
He still lives with his family
Even the war and the navy
Could not bring him to maturity.
- Daniel Amos's "Baby Game" (from ˇAlarma!) is about a female example. It's a satire of Christians who never bother to learn anything about their faith and just keep believing exactly what they did as a child.
Little birds are helpless, way up in the tree
They cry for mother almost constantly
But little birds must one day take their wing
I told her this, she threw her rattle at me
- The Lonely Island's "Threw It On The Ground" features the protagonist defiantly throwing a bunch of things on the ground for all sorts of stupid reasons, such as a hot dog because he's not "gonna be a part of your system", his "so-called girlfriend"'s cellphone because his dad's calling and "my dad's not a phone", and a kid's birthday cake to welcome him "to the real world, jackass" while insisting "I'M AN ADULT!"
- Implied to be the case with the subject of the song Stiches by Orgy. At one point the singer angrily says "Unsatisfied? You little girl!"
- "The Archer" by Taylor Swift says, "I never grew up, it's getting so old."
- The music video for "Free Will at Ease" by Skating Polly portrays this by showing Peyton dating a guy who flops between being portrayed by an adult actor and a literal little boy. He demonstrates both obnoxious man traits, like mansplaining music and groping Peyton's sister Kelli, and childish traits such as playing with his food and being a picky eater.
- The Vocaloid song The Lost One's Weeping by Neru has this gem as it's Wham Line in it's final chorus:
いつになりゃ大人になれますか (Why don't you grow up?)そもそも大人とは一体全体何ですか (What the hell is growing up?)
- The Arbuckle brothers in Garfield both have problems with this. Jon sometimes regresses to thumb-sucking and tantrum-throwing when he gets emotionally vulnerable. Doc Boy still needs his Security Blanket to sleep, childishly teased Jon when the latter got a girlfriend and was shown in the Christmas special to get a toy airplane as a present. Both also show childish happiness at hearing the same Christmas story read to them every year and opening presents. There seems to be an element of nurture to their behavior, as their mother still sees them as her little boys and treats them as such. In his more self-aware moments, Jon makes attempts to grow out of this, but Status Quo Is God dooms his efforts.
- Darryl and Wanda from Baby Blues aren't really that much more mature than their children (Zoe, Hammie and Wren) as Darryl can be seen engaging with childish activities with the kids and Wanda bawls like a baby when something goes really wrong for her.
- InSecurity has Sedine, a Cloud Cuckoolander Genki Girl who is so childish she makes Sam seem more like her babysitter than her husband, then there's Sedine's cousin Roy...
- Ted of Sally Forth (Howard) loves collecting geek memorabilia and trivia and is prone to being a Sore Loser. He's even referred to himself as such one time. There are some deconstructive elements with him, as his estranged relationship with his father is hinted to be why he regresses to childish demeanor as a coping mechanism and Sally has made it clear to him at least once that he has to become more of an adult if he wants to keep their relationship healthy.
- The main character in The Norm is this. This is deconstructed many times, with Norm genuinely struggling at adulthood and him trying to be mature contributing to his depression.
- The premise of Podcast: The Ride is the innate humor of "three childless men in their thirties" talking about Theme Parks for hours on end. Jason in particular is targeted for frequent jokes regarding how his height and love of sweets make him seem even more of a grown child.
- George Steele, after his face turn. Fans would instantly sympathize with "the Animal" as he tried to win over Miss Elizabeth, which sparked a legendary feud with Randy Savage. Several vignettes were also filmed featuring Steele, such as at the Detroit Zoo and at an ice cream factory (one which made ice cream bars featuring wafers imprinted with a WWF superstar); still later, he was paired with a hand puppet named "Mine."
- Alexis Laree in Bad Boys Of Wrestling. She mistook birth control for candy.
- Find an archive that houses Abyss's career (at least starting with the Abyss gimmick) and marvel as he gradually transitions from a Wrestling Monster in Puerto Rico and NWA to asking if Jacqueline on his lap means he's no longer a virgin in TNA.
- R-Truth after being betrayed by John Morrison on WWE Raw, rapidly descended into an madness and childlike behavior.
- The Rock's criticism of John Cena basically boiled down to The Rock seeing Cena as a giant child. Cena had a counter argument, though it didn't endear him anymore.
- Wrestlers who frequently throw tantrums when things don't go their way, such as Chris Jericho when he's a heel, Alicia Fox or Ken Anderson.
- Cabin Pressure gives us Arthur Shappey, the relentlessly cheerful and optimistic steward of the aeroplane who is gullible to the point of idiocy, gets ridiculously excited over Christmas, still lives with his mother, genuinely thinks it's possible for something to be bigger than the box it's in, has discovered the secret to true happiness, and thinks everything and everyone is utterly ''brilliant''. And who once killed a man.
- Willy Wonka in the 2013 musical version of Charlie and the Chocolate Factory is a downplayed version. He has a distinctly adult air of authority and elegance, but at the same time has childlike wonder, enthusiasm, impatience, creativity, and — to a lesser extent — innocence, rather Ambiguous Innocence at that.
- In Eurydice, the lord of the underworld is childish and petulant, best shown when he rides in on a tricycle in his failed attempt to seduce Eurydice, eventually determining she'd like him more if he were taller.
- Batman loves the circus in Holy Musical B@man!:
Alfred: You can't stay in your pillow fort and cry forever.
- The Green Role from the Reduced Shakespeare Company's Ragtag Bunch of Misfits. Being the Man Child of the group is his defining characteristic.
- The clown in Cirque du Soleil's Saltimbanco, Eddie, is quite childlike as he pulls pranks on others and engages an audience member in a pantomimed Wild West shootout. In fact, he might actually be the adult form of the Child seen early on, if a transitional scene is anything to go by.
- Peter Pan is one in Shrek: The Musical:
Peter: Maybe if we all close our eyes and clap really hard!
Pinocchio: Oh, grow up!
Peter: I won't grow up!
Pinocchio: You're thirty-four and need a shave!
- Tobias Ragg from Sweeney Todd: The Demon Barber of Fleet Street can be played several ways, and this is one of them. Bonus points if he is still childish because of insanity and/or mental handicap, both common portrayals. The Movie made him an actual pre-pubescent boy, a method that is much harder to pull off on-stage, mostly because labor laws require underage performers to be doubled.
- The Complete History Of America Abridged depicts Ronald Reagan as an irresponsible overgrown lap-boy with an undersized puppet body who calls Nancy "Mommy."
- Sanae Furukawa, the mother of Nagisa. She is around 40 years old, yet she is often quite emotional and childlike. This doesn't make her any less adorable, though.
- Fuuko Ibuko. As an adult in ~After Story~, she still acts rather childish and is more willing to play with children than interact with adults. Justified since she had been in a coma for a number of years, so she wouldn't have aged much mentally.
- Nagisa herself is a mild example. Even in her 20s, she's still rather sensitive, playful, and eccentric. Much like her mom, this makes her all the more cute and lovable.
- Miu Iruma from Danganronpa V3: Killing Harmony has a penchant for making sex jokes, calling her classmates virgins while giving juvenile nicknames, and generally saying whatever comes to mind without filtering herself, not that she seems to realise that she is acting in terrible taste. In addition to her childish behaviour, her report card shows that she likes watching TV shows for kids.
- Kyousuke from Little Busters! is a benevolent, more subtle example: because he's so obsessed with finding fun things to do, tends to be overdramatic and switch between extreme emotions, and doesn't always possess the greatest amounts of common sense (though that's not unusual in this game) he's commonly compared with a child.
- Minotaur Hotel: Storm tends to be pretty naive about most things, and would end up sounding like a child if it wasn't for the fact that he's a Minotaur with a deep voice at the age of 21. This is because he had a sheltered life, having neglectful parents, and a hostile environment in which no one approached him friendly. This is the reason why P is so hesitant on starting a relationship with him even though he's attracted to him, because he sees it as an Unequal Pairing.
- Fate/stay night: Saber is, we are told, not actually fifteen; after receiving her sword and becoming King Arthur, she didn't age over the next ten years, and she's really in her twenties. Not only does nobody mention how strange it is for her to have a romance with the seventeen year old main character, but she's as naive emotionally as a real fifteen year old, which is Hand Waved by claiming that as the king she had no personal life, or more specifically, she spent so much time keeping her emotions bottled away for the greater good that being put into a situation where she actually uses them leaves her vulnerable, not helped by the fact that her romance with the main character is one of the first times she legitimately felt romantic love for somebody else.
- At least Saber is reasonably mature, even if she's inexperienced and her wish is to childishly undo her mistakes. In Fate/Apocrypha we meet Mordred (Saber's child), who is not only actually about ten years old, but immature even for that age. She rarely listens when other people speak, spends a significant amount of time getting in fights with cats, and caused a rebellion against her father because she knew being king was killing Saber. The entire myth of King Arthur would have gone very differently if she had any ability to have a mature conversation with her father.
- Ciel from Tsukihime has a similar situation to Saber's going on, but in that case it's actually lampshaded in Kagetsu Tohya.
- Arcueid is a textbook example after she opens up with Shiki.