History Main / KiddieKid

* ''WesternAnimation/DextersLaboratory'': Dee Dee, who is elder to her titular brother, is implied to be a sixth grader. This would put her actual age somewhere between ten and twelve. However, she tends to behave as if she were much younger than Dexter, always [[TheThingThatWouldNotLeave invading his secret laboratory]], acting nosy to Dexter's business, and crying quickly over being snapped at. In terms of her more childlike aspects, she's a GirlyGirl who performs ballet, loves the color pink, [[AllGirlsLikePonies ponies]], and [[GirlsLoveStuffedAnimals stuffed animals]].

** Downplayed with 11/12-year-old Lincoln Loud, who mostly acts his age, but he still has a stuffed rabbit named Bun-Bun which he cares for with an affection most kids his age have outgrown.
** His friend Clyde also has shades of this since he is shown to be a fan of Blarney the Dinosaur, which is meant for a much younger age demographic.
** Luan is 14/15 years old yet has a fondness for puns, pranks, clowns, novelty toys, and childlike comedy in general.
** 13/14-year-old Lynn is not above throwing tantrums when she doesn't get what she wants and exhibits very poor sportsmanship for a PassionateSportsGirl. Her childishness is also exhibited in "Cereal Offender" where she rides on a shopping cart and wrecks many aisles, and in "Sitting Bull" where she plays on a tire swing in the backyard with her younger twin siblings, 6/7-year-olds Lola and Lana, which her older four sisters deem her immature for and are thus reluctant to hire her as the fifth babysitter.
** CJ Casagrande from the spin-off series ''WesternAnimation/TheCasagrandes'' is also a 13-year-old who likes playing pirates with his family, and with Lincoln. In this case, CJ's [[ChildrenAreInnocent childlike]] behavior is justified because he is confirmed to have Down Syndrome.
** Leni is 16/17, but due to being TheDitz and having a [[AttentionDeficitOohShiny short attention span]], she is often entertained by things that would entertain small children (like finger painting in "Schooled!" and a kiddie puzzle in "Lock and Loud") and in "Changing the Baby", she cries like a baby and even says, "Agoo".

* Tita Russell from ''VideoGame/TheLegendOfHeroesTrailsInTheSky'', not so much for her behavior (though she still has her moments of immaturity), but rather, the way the other characters treat her. She's 12, and a GadgeteerGenius prodigy at that, but all of the characters talk to her in an almost condescending way like they would a much younger child, including Estelle and Joshua, who are only four years older than her! This forms a substantial part of her CharacterDevelopment, as being treated like a kid frustrates her to no end, and she takes on increasing responsibility and danger to prove to the competent adults that she can pull her own weight with the best of them.

You turn on the TV and start watching it. Apparently, some child actor is guest starring. But wait a minute. How old is his character? He says he's X, but he's acting like X minus 5. What kind of 14-year-old gets real excited over a balloon? 10-year-olds don't ([[PeripheryDemographic usually]]) watch Creator/NickJr! Wait, a 12-year-old [[StillBelievesInSanta still believes in the Tooth Fairy]]? A 15-year-old is still playing with toys? To put it simply, that character is a Kiddie Kid.

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 a mental disability, such as autism.

* in the '' Literature/RamonaQuimby'' series, Ramona herself tends to behave as someone her age should, as is also the case for her sister Beezus and best friend Howie. Such is not the case, however, with Howie’s little sister Willa Jean. In the first book, Ramona is four years old and Willa Jean is around two, able to walk and say a few words. By the last book, Ramona is in the fourth grade while Willa Jean is at best around three or four, able to speak better but still “messy” and too young for school, with a toddler’s tantrums, etc.

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 mental deficiency.

In most 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 mental deficiency.

* On ''Manga/SailorMoon'' Usagi counts as one. At fourteen, she starts out as a carefree crybaby who loves childish things, just wants to have fun and can't keep up with the kind of schoolwork expected of her age. A RunningGag is that she still can't write kanji despite her age due to how BookDumb she is, so by Japanese standards she essentially writes like an elementary school kid. She grows out of it after she spends some time as Sailor Moon. Except the Kanji thing. Even Neo Queen Serenity, proper, regal and mature as she is still cant do Kanji correctly. The other guardians comment on how this shows Usagi is still the same after so long.

* Usagi from ''Manga/SailorMoon''. At fourteen, she starts out as a carefree crybaby who loves childish things, just wants to have fun and can't keep up with the kind of schoolwork expected of her age. A RunningGag is that she still can't write kanji despite her age due to how BookDumb she is, so by Japanese standards she essentially writes like an elementary school kid. She grows out of it after she spends some time as Sailor Moon.

** Downplayed with 11-year-old Lincoln Loud, who mostly acts his age, but he still has a stuffed rabbit named Bun-Bun which he cares for with an affection most kids his age have outgrown.

** Luan is 14 years old yet has a fondness for puns, pranks, clowns, novelty toys, and childlike comedy in general.
** 13-year-old Lynn is not above throwing tantrums when she doesn't get what she wants and exhibits very poor sportsmanship for a PassionateSportsGirl. Her childishness is also exhibited in "Cereal Offender" where she rides on a shopping cart and wrecks many aisles, and in "Sitting Bull" where she plays on a tire swing in the backyard with her younger twin siblings, Lola and Lana, which her older four sisters deem her immature for and are thus reluctant to hire her as the fifth babysitter.

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

* 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, despite the fact that this girl was likely his age.

You turn on the TV and start watching it. Apparently, some child actor is guest starring. But wait a minute. How old is his character? He says he's X, but he's acting like X minus 5. What kind of 14-year-old gets real excited over a balloon? 10-year-olds don't ([[PeripheryDemographic usually]]) watch Creator/NickJr! Wait, a 12-year-old [[StillBelievesInSanta still believes in the Tooth Fairy]]? What 15-year-old still plays with toys? To put it simply, that character is a Kiddie Kid.

You turn on the TV and start watching it. Apparently, some child actor is guest starring. But wait a minute. How old is his character? He says he's X, but he's acting like X minus 5. What kind of 14-year-old gets real excited over a balloon? 10-year-olds don't ([[PeripheryDemographic usually]]) watch Creator/NickJr! Wait, a 12-year-old [[StillBelievesInSanta still believes in the Tooth Fairy]]? Most 15-year-olds stopped playing with toys years ago. To put it simply, that character is a Kiddie Kid.

You turn on the TV and start watching it. Apparently, some child actor is guest starring. But wait a minute. How old is his character? He says he's X, but he's acting like X minus 5. What kind of 14-year-old gets real excited over a balloon? 10-year-olds don't ([[PeripheryDemographic usually]]) watch Creator/NickJr! Wait, a 12-year-old [[StillBelievesInSanta still believes in the Tooth Fairy]]? A 15-year-old still plays with toys? To put it simply, that character is a Kiddie Kid.

You turn on the TV and start watching it. Apparently, some child actor is guest starring. But wait a minute. How old is his character? He says he's X, but he's acting like X minus 5. What kind of 14-year-old gets real excited over a balloon? 10-year-olds don't ([[PeripheryDemographic usually]]) watch Creator/NickJr! Wait, a 12-year-old [[StillBelievesInSanta still believes in the Tooth Fairy]]? To put it simply, that character is a Kiddie Kid.

* Shapey, Orel's younger [[spoiler:half-]]brother from ''WesternAnimation/MoralOrel'', is seven years old, but behaves like a toddler. Unlike most examples, it isn't treated as normal, as it's clear that Shapey's issues are the result of his dysfunctional household. [[spoiler:In the DistantFinale, it's implied that he was able to outgrow it and become a functional adult.]]
** Orel’s father, Clay, was shown to also not act his age, acting like a 5 or 6 year old when really he was 12. This was because his mother spoiled him rotten, and all the attention she gave him made him constantly act like her precious little baby, which greatly annoyed his father.

* ''WesternAnimation/{{Rugrats}}'': Downplayed for Chuckie. He's two and while he mainly behaves like a two-year-old, the only word he can say [[BabyLanguage to the grownups]] is "No".

You turn on the TV and start watching it. Apparently, some child actor is guest starring. But wait a minute. How old is his character? He says he's X, but he's acting like X minus 5. What kind of 14-year-old gets real excited over a balloon? 10-year-olds don't ([[PeripheryDemographic usually]]) watch Creator/NickJr! Wait, they [[StillBelievesInSanta still believe in the Tooth Fairy]]? To put it simply, that character is a Kiddie Kid.

* 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.

* 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.

* 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 psychically 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).

* 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.

[[caption-width-right:203: [[DamnedByFaintPraise Nice drawings you have there, Molly.]]]]

'''Mackenzie Zales:''' ''Godammit'', Katelynn! I'm sorry, Deandra.\\

* Film/ChildsPlay2019 aged Andy Barclay up to 13 (from 6 in the original film). It's hard to imagine a 13-year-old boy being excited over a doll like Chucky, never mind that it's {{creepy|Doll}}-[[UncannyValley looking as hell]] even before it goes homicidal.

* In ''Film/DownInTheDelta'', the autistic toddler Tracy still sleeps in a crib, even though it's noted that she's too old for it.