Children all over the world believe in Santa Claus and the magic of Christmas. However, the majority of children outgrow this belief by their teens, accepting that Santa is a story told to kids to keep them happy at Christmastime.
Well, not this guy. This character still believes in Santa Claus well past the age children usually outgrow this belief (at least in their mid-to-late teens, some examples even involve grown adults). This is meant to mark them as innocent, childish, or even delusional in some way; it can also bolster existing Manchild/Kiddie Kid or Cloud Cuckoo Lander characterization. They may get made fun of for this belief, so some may move past it over the course of the story.
Other times an older person's belief in Santa is treated as an endearing quirk, especially if the true believer is someone you wouldn't expect to be one, like a gruff soldier or a haughty Alpha Bitch. In this case, it could be a sign of Not So Above It All.
Although Santa Claus is the most common figure to get this treatment, it can still apply to other prominent mythical figures of childhood, like the Tooth Fairy or the Easter Bunny.
Can overlap with Santa's Existence Clause, where Santa is Real After All, validating the belief of someone (who may or may not be a child). May come up during a Christmas Episode. Compare Santa Ambiguity where Santa's existence is hinted but never really confirmed.
- Noragami: An extra chapter reveals that Yato, a young and seldom-acknowledged god, still believes in Santa.
- In Love Live!, Maki still believes in Santa Claus. Nico was ready to make fun of her for it until Honoka and Rin stop her so she wouldn't shatter Maki's innocence.
- In Lucky Star, it's revealed that Konata still believes in Santa Claus when Tsukasa asks her when she stopped believing in him. Turns out Konata's father told her that the Christmas presents he gave to Konata every year were from Santa Claus himself.
- Samurai Pizza Cats: In the Japanese version of the Christmas Episode, Polly Esther believes in Santa Claus and is mocked for it by the other characters.
- In an early Doonesbury, Mike relates to Zonker how he cried when he found out as a child that there was no Santa. He starts to ask Zonker how old he was when he learned, but Zonker interrupts by bawling right then and there.
- In The Loud House fanfiction Ace Savvy and the Full House Gang: Checkmate, Leni, true to her character, still believes in Santa at sixteen and mistakes a bearded guy named Reginald Barnum for Santa.
- 12 Days of Smashmas: Marth, despite being a young adult, still believes in Santa Claus. In contrast, the much younger Ness is Wise Beyond His Years and does not.
- In Finding Nemo, one bonus feature reveals that despite being fully grown and a biology teacher, Mr. Ray thinks there's an underwater tooth fairy, who has a full-time job collecting sharks' teeth.
- In The Christmas That Almost Wasn't, Sam Whipple is a rather childish man. One of the ways this is shown is that he explicitly still believes in Santa.
- Elf: Buddy is an adult Manchild with a Pollyannaish personality who still believes in Santa, which is played as a weird quirk. The plot of the film involves Buddy trying to get the rest of the adult world to renew their belief in Santa. Justified, as Santa is Buddy's adoptive father, so he knows for sure that Santa exists.
- George of Sydney White is a Cloud Cuckoo Lander who still believes in Santa, among other details.
- In Little Women, when the March sisters are trying to figure out who provided the lavish Christmas feast they find waiting for them (it was Mr. Laurence), 13-year-old Beth guesses "Santa Claus" and 12-year-old Amy guesses "the fairies." This isn't played for laughs, though it just highlights the girls' innocence because the March parents believe in letting children be children as long as possible.
- In the Bert Diaries books, Lill-Erik still believes in the Easter Bunny despite being well into his teens. What's more, he lives in fear of it. Every Easter he refuses to go outside for fear of running into the Easter Bunny in a dark alley.
- Friends: Phoebe (the kookiest of the titular friends) and Joey get into a debate about whether completely selfless good deeds exist or not, with Joey taking the side of them not existing. While making his point, he mentions "the deal with Santa Claus". Later, Phoebe follows up on that remark to make sure Joey meant that Santa Claus doesn't exist. After getting the confirmation, Phoebe spends a few moments staring wide-eyed into space.
- Brittany Pierce of Glee is the show's resident ditz, and asks Artie with utmost seriousness what he asked for from Santa during one of the Christmas episodes.
- The Many Loves of Dobie Gillis: High school beatnik Maynard still believes in Santa Claus.
- In the Monk episode "Mr. Monk Goes to the Asylum", one of the other adult patients still believes in Santa and is instrumental in solving the case.
- Jade is one of the haughtier members of the teen cast of Victorious, so revealing she still believes in Santa Claus in her fourth "What I Hate" video makes her more endearing.
- The Most Popular Girls in School: As shown in episode 38, Trisha (who is a high schooler) still believes in Santa.
Trisha: Well, hey, at least you get to meet Santa, right? I mean, the man himself.Bridget: Wait. You still believe in Santa?Trisha: Well, I haven't been nice all year for nothing.Bridget: So your parents never told you that he wasn't real?Trisha: Oh...they try to tell me every year. But every year, I come back, and look who's here! So who's got egg on their face now?!
- In Alluna And Brie, Max, who happens to be a ditzy idiot (if a really good cop), reveals that she still believes that Santa brings presents every Christmas Eve while trapped in a magic lamp over Christmas. When everyone else points out that Santa doesn't exist, Max is devastated. However, the sequel to Max's Big Bust: A Captain Nekorai Tale, which continues this story, reveals that Santa is indeed real, though not quite the same as the legend.
- Yukiho Hagiwara in The Idolmaster is revealed to still believe in Santa at age 16. There is another scene where Chihaya, age 15, is implied to believe in Santa but given the context it's possible she was joking.
- Magia Record: Puella Magi Madoka Magica Side Story: The Page I Write On This Holy Night reveals that The Ingenue Ren Isuzu still believes in Santa Claus despite being 15 years old.
- Metal Gear Solid: Peace Walker: In the briefing file about NORAD, it is revealed that Big Boss, despite being a badass Super Soldier, still believes Santa exists and refuses to listen to Huey's reason.
- Grandma Got Run Over by a Reindeer: Both Grandma Spankenheimer and her grandson, Jake, believe the big Christmas man is real despite the cynical nature of the rest of the family (the grandpa is implied to believe too, but his senility make it hard to tell). This ends up helping Jake find his grandmother since his letter to Santa the following year asking to find her shows Santa someone in Citiville still believes in him. And coincidentally enough, it allows them to finally put a name to said Grandmother who lost her memory after, well, Santa accidentally ran her over and Santa had to take her to the North Pole to treat her injuries.
- Justice League: When Martian Manhunter spends Christmas with the Kents, he learns that Superman (an otherwise mature superhero) genuinely believes Santa Claus is the one who wraps his presents in lead (so he can't see through them with X-Ray vision). This is an indicator of Clark's down-home wholesomeness as a person. Although, Clark might be justified considering the DC Animated Universe is as much of a Fantasy Kitchen Sink as its comic counterpart.
- In a Martha Speaks episode, somebody phones up Dr. Pablum and Otis Weaselgraft, who have Martha captive, pretending to be Santa. Despite being grown men and Dr. Pablum being a scientist, the two only get suspicious when they realise that they'd be on the Naughty List.
- Paradise PD: Oafish manchild loser Dusty (who is a cop) thinks Santa is real. Turns out he's right.
- In the Recess Christmas special "Yes Mikey, Santa Does Shave," sensitive Gentle Giant Mikey is the only fourth grader, or at least the only one in his group of friends, who not only still believes in Santa, but still thinks the "Santas" who show up at malls and other public events are the real deal. After he learns the truth about the latter, he loses his belief in Santa altogether and becomes depressed, but in the end it turns out that Santa is Real After All.
- Exaggerated in Trolls: The Beat Goes On!. In the episode "Marshtato Fairy", it's shown that, as a standard for Troll society, every Troll believes in their entire life about the existence of a titular Marshtato Fairy character, who is responsible for the supposed annual Marshtato harvest. The only Troll to have known the truth behind the myth thus far was Branch, but he decided to not tell it in order to avoid ruining the Trolls' life.