History Main / KiddieKid

Can be a side-effect of CompetenceZone. Contrast WiseBeyondTheirYears and ActingYourIntellectualAge. Related to MenaceDecay. When it's an ''adult'' behaving younger than their stated age, it's ManChild and/or OneOfTheKids.

* ''WesternAnimation/{{Braceface}}'': In the episode "Act Your Age" 14-year old Sharon dates a boy named Pablo and it turns out he's only 12 years old. However at several points in the episode he behaves like someone younger than that, he wears shoes with velcro (which most boys his age don't) and his 13th birthday party has clowns and loot bags (something Sharon even mentions her younger brother doesn't have at his parties anymore) Most boys that age would think they were too old for something like that. However, this is justified to show how much younger he is than Sharon.

* ''WesternAnimation/SpongeBobSquarePants'': Pearl may be a teenager, but she dreams about having tea parties, and on occasion, she makes drawings of sea-unicorns.

* ''WesternAnimation/MiraculousLadybug'': Chloé Bourgeois is 14/15 and very much behaves like she was 6, still carrying around a teddy bear and believing in things such as Santa Claus and cooties as well as having the temper of a literal spoiled child. Most of this stems from her MissingMom and her father constantly enabling her behavior. Neither parent, however, is willing to own up to this.

* ''WesternAnimation/RosiesRules'': Crystal boasts about how she's 12 and very grown up, only to squeal seconds later when she sees balloon animals. Justified, as a preschool show requires that pretty much ''everyone'' act childish.

* Possibly why Denny from ''Film/TheRoom'' acts so weird--he appears to be in his late teens or very early twenties, and was played by a [[DawsonCasting 26-year-old]], but acts like a (strange) little kid who's just on the cusp of puberty and doesn't quite know how to handle it.

In more justified cases, the kid in question has not had a conventional upbringing (e.g. they're orphans, homeschooled), causing them to have a naïve outlook. They may also act younger than their age due to being neurodivergent. ValuesDissonance may also play a part: in Japan, for example, childishness is considered cute (at least in girls).

** Michael and Deanna’s son Robin acted more like a baby than a toddler, rarely speaking in sentences, going through PottyFailure well after he was fully toilet trained and gullible (he infamously ate a mud pie believing it was chocolate ''after he watched Meredith make it.'') Many fans and haters [[DiagnosedByTheAudience believe that Robin is on the autism spectrum or has some kind of learning disorder.]]

* PlayedForDrama in ''Fanfic/InfinityTrainBlossomingTrail'': Hop is usually depicted as a pre-teen who is capable of handling himself and is off on his own adventure to be a great Trainer. However, by the time we cut back to him when he's been stuck in The Fog Car (aka ''Silent Hill''), he's somehow mentally regressed to a six or seven-year-old boy, acting affectionate and childlike to [[VideoGame/SilentHillHomecoming Alex Shepherd]] to the point he's asking for bedtime stories and drinking chocolate milk and butter cake before bed. This is presumably due to what Walter and Henry wish to enact for a ritual, needing seven people to embody certain aspects and Hop represents "Delight".

* A downplayed version in ''ComicStrip/ForBetterOrForWorse'' since the characters are toddlers, but 2-3 year old Leah and Richard are treated more like infants. They still drink from bottles despite kids that age drinking from sippy cups, and Richard still eats mushed up food and speaks in simple babble such as "Ya-Gah" despite kids that age eating the same food as adults and speaking at least 2-3 word sentences.

* ''WesternAnimation/Braceface'': In the episode "Act Your Age" 14-year old Sharon dates a boy named Pablo and it turns out he's only 12 years old. However at several points in the episode he behaves like someone younger than that, he wears shoes with velcro (which most boys his age don't) and his 13th birthday party has clowns and loot bags (something Sharon even mentions her younger brother doesn't have at his parties anymore) Most boys that age would think they were too old for something like that. However, this is justified to show how much younger he is than Sharon.

* Steve Smith from ''WesternAnimation/AmericanDad'' is a DependingOnTheWriter version of this. While most of the time he acts like your stereotypical HormoneAddledTeenager, some episodes give him childish mannerisms and interests such as toys and playing pretend. He even still has a babysitter in one episode, in spite of being around the same age as her.
* Macie turns into one in the ''WesternAnimation/AsToldByGinger'' episode "Family Therapy" after her parents start treating her like a four-year-old after forgetting her birthday. She starts to enjoy playing on a Rocket Tykes Swingset and a My First Jungle Gym, going to the local SuckECheeses, has her thirteenth birthday party at a petting zoo (with kiddie-style decorations), and even starts dressing more like a four-year-old. Ginger notes that Macie is liable to get bullied if this continues, and repeatedly tries to fix the problem. Macie gets annoyed at Ginger's intervention (and ends up being proven right when the most popular kids in school think the petting-zoo party is [[TrueArtIsIncomprehensible some sort of post-modern statement]] and dub it the coolest thing they've ever seen). In an interesting subversion of the trope, the episode ends with Macie admitting that she ''knows'' this behavior is far too juvenile for her: she's just making up lost time with her parents, and assures Ginger that she'll be talking with them about treating her like a teenager soon. Given that she ends up back to her old self, this presumably works.

* In the ''WesternAnimation/Braceface'' episode "Act Your Age" 14-year old Sharon dates a boy named Pablo and it turns out he's only 12 years old. However at several points in the episode he behaves like someone younger than that, he wears shoes with velcro (which most boys his age don't) and his 13th birthday party has clowns and loot bags (something Sharon even mentions her younger brother doesn't have at his parties anymore) Most boys that age would think they were too old for something like that. However, this is justified to show how much younger he is than Sharon.
* Something is not right with Cleveland Jr. from ''WesternAnimation/TheClevelandShow''. Most people just view him as an optimistic nerd, but he also can't let go of some childhood memories. He still plays with his "Larry the Leopard" stuffed animal, and acts as though it's a real person, he often gets easily tricked by Rallo, who is ''5 years old'', and he wants his dad to kiss him goodnight. This is [[LampshadeHanging explicitly stated]] as weird in-universe, and others his age typically avert this trope [[RuleOfFunny unless it's funny.]]
* Almost every member of the ''WesternAnimation/CodenameKidsNextDoor'' is an exaggerated stereotype of children, even the nine- to twelve-year-old ones who should be more mature. They all love soda pop, [[StockYuck hate vegetables]], and act rather innocent.

* Chris from ''WesternAnimation/FamilyGuy'', DependingOnTheWriter. Some episodes will have Chris behave like a normal teenager, which has become more common in recent seasons, and others will make him easily entertained and somewhat shallow minded, as well as playing childish tricks anybody his age could see through, at age 15. Since his father is a ManChild, and since he is very similar to him, it may run in the family.
* Cubert from ''WesternAnimation/{{Futurama}}'' is a 12/13-year-old who looks and acts like he's around 9. A plot point of one episode was about how he felt the need to imitate everything he saw on his favourite TV show, even if it didn't make sense.
* Harold from ''WesternAnimation/HeyArnold'' is arguably one of the most immature characters in Mr. Simmons' 4th grade class, as he often cries and has been shown playing with a Barney Expy doll on multiple occasions, and yet he's actually ''four years older'' than the rest of his class, since he celebrates his bar mitzvah in one episode.

* ''WesternAnimation/JimmyTwoShoes'' is a teenager, yet he's very excitable, gullible, and childish and seeks for fun wherever he goes.

* Bobby Hill of the later episodes of ''WesternAnimation/KingOfTheHill''. Even though he is supposed to be 14 years old, he occasionally acts very childish. This is mainly a case of DependingOnTheWriter; in some episodes he is fairly intelligent and mature and in others he is incredibly whiny, foolish, and immature. The 13th season has some of the worst offenders, with episodes like "Master of Puppets" and "Reborn on the Fourth of July".

* Charlotte from ''WesternAnimation/MakingFiends'' is a 4th-grader with the mindset of a pre-schooler, showing a considerably egregious imagination, enjoying toys and games most children of her age would have outgrown from, singing childish songs, and being overly optimistic about pretty much everything.
* Max from ''WesternAnimation/MaxAndRuby'' starts out at 3 and speaks in one word sentences. As a 4-year-old he speaks in complete sentences but not in fluent English. He is the only kid in his class unable to do so.

* ''WesternAnimation/MiraculousLadybug'': Chloé Bourgeois is 14/15 and very much behaves like she was 6, still carrying around a teddy bear and believing in things such as Santa Claus and cooties as well as having the temper of a literal spoiled child. Most of this stems from her MissingMom and her father constantly enabling her behavior. Neither parent however is willing to own up to this.
* ''WesternAnimation/TheOwlHouse'': Luz Noceda is a high school-aged teenager and has the rowdiness, wonderment, and imagination of a child at least in their elementary years. She has even played with dolls at her current age before and is interested in action figures. Justified, as it’s revealed that her fixation with her fantasies partly stems from years of social isolation from her peers, pressure from society’s expectations and, most importantly, [[spoiler: from her grief following the death of her father at young age]].
* A CompressedVice in the ''WesternAnimation/{{Recess}}'' episode "Bonky Fever," where Mikey becomes obsessed with Bonky the Dragon (a parody to Barney), and starts to act more and more childish as time goes on. This includes crying like a baby after getting gently tapped with a dodge ball, throwing a temper tantrum in the cafeteria after the lunch lady refused to give him an extra pudding for his Bonky doll, and asking T.J. to walk him to the bathroom so he can "go potty." This is because he's turning ten, and he's starting to realize that GrowingUpSucks.

* The ''WesternAnimation/SonicTheHedgehogSatAM'' version of Tails is intended to be ten years old, which would make him older than his game counterpart, who is stated to be eight. However, he acts as if he were junior to [[VideoGame/SonicTheHedgehog his game counterpart]]; Tails is not allowed to be a Freedom Fighter for his own safety, which closely matches the way adults would [[SurprisinglyRealisticOutcome realistically]] treat a ten-year-old, but it still doesn't explain his immature personality. He also calls Sally "Aunt Sally" despite there only being a slight age gap between them.

* Pearl from ''WesternAnimation/SpongeBobSquarePants'' may be a teenager, but she dreams about having tea parties, and on occasion, she makes drawings of sea-unicorns.
* Steven from ''WesternAnimation/StevenUniverse'' has a VagueAge for the first season and a half, but in "Steven's Birthday" is revealed to be turning fourteen. His MuggleBestFriend and LoveInterest, who's not even thirteen but is more mature, is shocked. Aside from the fact that he still sleeps with a teddy bear and generally acts like he's under eleven, Steven also [[OlderThanHeLooks looks quite younger]]: because [[HalfHumanHybrid his mother]] was [[TheAgeless an ageless alien]] whose species have their physical forms match their mental ages, this ended up applying to Steven as well, with his dad showing Connie a scrapbook showing that Steven hasn't physically aged since he was eight. ''[[WesternAnimation/StevenUniverseFuture Future]]'' would finally have a more mature (but emotional unstable) Steven who finally looks his age (at that point, 16).

* The main characters of ''WesternAnimation/TinyToonAdventures'' are treated as teenagers, and in their less wacky moments usually act like them (though it fluctuates). But never Dizzy Devil, Lil Sneezer, or Elmyra, who, despite being in the same class as the other characters, consistently act far younger than they ought to (which [[KavorkaMan doesn't stop Dizzy from having multiple attractive human girlfriends]].)
* Hank and Dean Venture in ''WesternAnimation/TheVentureBros'' are around sixteen when the series begins, and yet their behaviors and speech patterns are on par with those of elementary schoolers in a 50s sitcom. This is mainly played for laughs in earlier seasons, mocking squeaky-clean supposed teenagers in older media, but it becomes increasingly justified later, as it's revealed just how horribly sheltered their upbringing is and that they've lost a fair bit of life experience as a result of being clones. By the fourth season, they end up forced to mature somewhat, though they're still a few years behind their peer groups.

* ''WesternAnimation/TheOwlHouse'': Luz Noceda is a high school-aged teenager and has the rowdiness, wonderment, and imagination of a child at least in their elementary years. She has even played with dolls at her current age before and is interested in action figures.

** Ralph Wiggum is this combined with {{Cloudcuckoolander}} and AmbiguousDisorder, he often acts more like a four or five-year-old rather than an eight-year-old.

In more justified cases, the kid in question has not had a conventional upbringing (e.g. they're orphans, homeschooled), causing them to have a naïve outlook. They may also act younger than their age due to being neurodivergent.

* In the ''Series/{{Emergency}}'' episode "Alley Cat," the firemen rescue a girl from a plane crash who looks about twelve, but acts closer to four. She calls her parents Mommy and Daddy, refers to her injured, unconscious father as "asleep in the plane," does an impression of a lion, and even calls her mother's bandages a "funny hat" and asks if she can have one. The adults around her act accordingly, with lines like "Why don't you one, two, three, four drink your milk?" As in ''Midnight Caller'', the children of ''Emergency!'' usually act at least somewhat like their age, so her behavior is jarring.

* In ''Film/TheMajorAndTheMinor'', Ginger Rogers must pretend to be 12, which she does by acting like she's 6.

** Leni, the second of Lincoln's older sisters, is 16/17, but due to being TheDitz and having a [[AttentionDeficitOohShiny short attention span]], she's often entertained by things that would entertain small children (like finger painting in "Schooled!" and a kiddie puzzle in "Lock and Loud"). In "Changing the Baby", she cries like a baby and even says, "Agoo".

* ''WesternAnimation/KimPossible'': Ron Stoppable tends to dip into this territory. A prime example would be the "Coach Possible" episode where, unlike most high schoolers, he doesn't mind hanging out at the local SuckECheeses and is horrified when the villains steal, then redress his favorite animatronic. ''"PIZZAPOTAMUS!!! [[BigNo NOOO!!!"]]''

* Charlotte from ''WesternAnimation/MakingFiends'' is a 4th-grader with the mindset of a pre-schooler, showing a considerably egregious imagination, enjoying toys and games most children of her age would have outgrown from, singing childish songs, and being overly optimistic and excited about pretty much everything.