Codename: Kids Next Door



Codename: Kids Next Door (2001-2008) is an original animated series from Cartoon Network about a team of five ten-year-olds who are members of a secret organization that fights adult tyranny. It's much better than it sounds.

The idea grew out of side characters for Mr. Warburton's failed series Kenny and the Chimp. The show featured five kids who lived next door to Kenny with no parental supervision. The five were simply troublemakers who enjoyed terrorizing the neighborhood. When the show fell through, they were retooled into the stars of their own show. The pilot was submitted for Cartoon Network "Big Pick Weekend", where viewers were allowed to vote on the next cartoon series. Kids Next Door reached the final three and was ultimately the winner.

The five kids became Sector V, a Five-Man Band in the worldwide organization known as the Kids Next Door. Numbuh One, The Hero, is a Properly Paranoid Conspiracy Theorist who is always seen wearing sunglasses (and has no hair). Numbuh Two, The Smart Guy, is an inventor known for cracking an Incredibly Lame Pun at inappropriate times. Numbuh Three, The Chick, is The Ditz of the team, constantly happy and serving as the team doctor. Numbuh Four, The Big Guy, is a Book Dumb kid who holds an invaluable amount of street smarts. Numbuh Five, The Lancer, is the only sane girl trying desperately to keep the team together.

Together, the KND of Sector V fight alongside their compatriots-in-childhood against numerous villains -- including the The Delightful Children From Down The Lane (and their creepy father, Father), Numbuh Five's traitorous teenage sister Cree, and the Corrupt Corporate Executive Mr. Boss -- who hate children and want them enslaved.

The show was known for its consistent continuity and its use of the Story Arc, as well as several Parental Bonus moments -- including an Affectionate Parody of the Animatrix short "The Second Renaissance" and a Musical Episode starring, of all bands, GWAR -- that attracted fans outside its intended audience. Another one of the show's big draws was the aversion of the Spotlight-Stealing Squad, Invincible Hero, and Failure Hero tropes; a new episode can actually have suspense over who's going to win or lose, and it's hilarious and/or awesome either way.

Episodes followed a specific naming pattern: the episode title is always "Operation: [X]" -- where [X] is an acronym (as an example: "T.E.E.T.H.") -- and both the acronym itself and the phrase it stood for (using the prior example: "Tooth Extracting Enemy Terrorizes Headquarters") served to give viewers a general idea of the episode's plot.

Kids Next Door ended after six seasons, one movie (Operation: Z.E.R.O.), and a crossover with The Grim Adventures of Billy and Mandy ("The Grim Adventures of the KND"). The Grand Finale, "Operation: I.N.T.E.R.V.I.E.W.S." ("It's Now The Extra Really Very Interesting End Wrap-Up Story"), answered a few questions. There are no DVD box sets, but various episodes have been released on compilation sets.

This show now has a character sheet.

This series has nothing to do with Girl Next Door.

""In the name of the One Supreme Ultra DNK Leader, Welcome... to the worst day of your lives.""
 * Abnormal Ammo / Edible Ammunition: Goes hand-in-hand with the 2×4 technology used by the KND, but used by other organizations and villains as well. The Six Gum Gang uses revolvers loaded with already-chewed gum, a sea coffee-drilling rig is equipped with coffee-bean turrets and one episode even has the U.S. government using giant robots that shoot bubblewrap.
 * Adorably Precocious Child: Most, if not all male KND operatives fit the description to perfection.
 * Adult Child: A good number of the villains, pretty ironically.
 * Adults Are Useless: Adults in the series tend to be evil or clueless.
 * Affectionate Parody: Let's see, we got...
 * The Matrix (even a parody from The Animatrix);
 * The Lord of the Rings
 * X-Men
 * Alien
 * Jurassic Park
 * Pirates of the Caribbean
 * Minority Report (yeah you read right)
 * Star Trek
 * Star Wars
 * Hero
 * Dragonball Z (part of a Rashomon Style episode)
 * West Side Story of all things.
 * Hell, even Baldur's Gate is given a Shout-Out to in one episode (the character Moosk is Minsc from the game).
 * Numbuh Five's solo, candy-related adventures frequently bear an uncanny resemblance to the exploits of one Henry Jones, Jr.
 * AI Is a Crapshoot: The AI of Sector V's treehouse starts singing "Daisy Bell" when Nigel tries to attend Lizzy's sister's wedding.
 * All According to Plan: A plot twist so common that it's also a Running Gag for one character for a time.
 * All Just a Dream: A few episodes end this way, most of the time with an Or Was It a Dream? vibe.
 * Angels Pose: The series' logo.
 * Annoying Younger Sibling
 * Numbuh Two's little brother Tommy.
 * Numbuh 86's little brothers. No wonder she hates boys. (Though this in her own words. When shown, its revealed they're not as bad as she made them out to be.)
 * Numbuh Three's sister, Mushi. Which is ironic as they actually started out getting along with each other.
 * Numbuh 362's little brother Harvey, Numbuh 363, who constantly antagonizes Numbuh One.
 * Numbuh 4's baby brother Joey.
 * Cree considers Numbuh 5 to be this to her.
 * Anthropomorphic Food: Grandmother Stuffem creates this to force itself into kids' mouths.
 * Anti-Villain: Count Spankulot makes it a point to only spank children who deserve it.
 * Art Evolution: Over the course of the series, the animation became more consistent and the colors became richer.
 * Art Shift: "Operation: R.E.P.O.R.T."
 * Ascended Fanboy:
 * Asian Airhead: Kuki Sanban (a.k.a. Numbuh Three) is effectively like a younger, prepubescent Hay Lin. An adorable, girly, kindhearted, rather prissy girl who is personified as being extremely scatterbrained. That Other Wiki says that she is only acting stupid so she doesn't feel sad.
 * Assumed Win / Crack Defeat: "Operation: E.L.E.C.T.I.O.N.S."
 * Author Appeal: Humongous Mechas.
 * Authority Equals Asskicking: If you're Supreme Leader, it's common knowledge you're a great fighter. I.e.: Numbuh Zero, 100, 274 and 362. Especially 362.
 * Badass
 * Cree Lincoln
 * Moose; he's the only adult beside Monty Uno who has Numbuh One's full respect, for very good reasons.
 * Badass Adorable Army: The entire Kids Next Door, though the "adorable" part may depend on certain operatives.
 * Badass Beard: Captain Stickybeard, of course.
 * Badass Boast: There are quite a few, in particular epic line in "Operation: P.O.O.L.":

"Stickybeard: (to Dumb John Silver) You're supposed to be an EVIL pirate!"
 * Badass Santa
 * Badass Family / Big Screwed-Up Family: The Unos, so very much. On one side, . On the other side, though,.
 * The Bad Guy Wins: As noted above, definitely present.
 * Balloon Belly: All of Sector V after Gramma Stuffum's attack in "Operation: N.O.-P.O.W.U.H.".
 * Bamboo Technology: Actually, two-by-four technology.
 * Banana Peel: In "Operation: S.N.O.W.I.N.G.", Numbuh One throws some banana peels before a quadruped Humongous Mecha (straight out of The Empire Strikes Back). The mecha pilots burst into laughter at this sight, but then their vehicule steps on a peel in the snow... and it immediately topples to the side.
 * Baseball Episode: "Operation: B.R.E.A.K.U.P."
 * Bathroom Break Out: President Uno does this during "Operation: W.H.I.T.E.H.O.U.S.E.".
 * Beach Episode: "Operation: B.E.A.C.H."
 * Beard of Evil: Negative Numbuh Four in "Operation: P.O.O.L.".
 * Belligerent Sexual Tension: Short-fused shorty Numbuh Four and Genki Tsundere Numbuh Three. Truly, a destined pair.
 * Be Quiet Nudge: Numbuh Five is usually the one to elbow her teammates when they need to shut it, like with Numbuh Four at the end of "Operation: R.O.B.B.E.R.S.", or Numbuh Three in "Operation: C.A.K.E.D.-F.I.V.E.". Note that it hardly works on the latter: if you truly want Kuki to shut up, you need to gag her.
 * Berserk Button
 * Numbuh Three: "Toys? I don't want toys. I WANT REVENGE!!!"
 * DO NOT HARM NUMBUH 4's LITTLE BROTHER (OR HIS CRUSH, NUMBUH 3) IN FRONT OF HIM.
 * You're going to put Numbuh 83 in a dark room!? You fool!
 * Saying anything anti-feminist around Numbuh 86 is a big No-No.
 * Also, never call Numbuh 86 "Toots", as Numbuh 2 learned the hard way.
 * Beyond the Impossible: They have a moon base and it looks to be made out of gum.
 * BFG: Including, but not necessarily limited to ones that shoot kangaroos, mattresses, and grizzly bears.
 * Big Bad: Alternates between Father and Mr. Boss
 * Big Good: Numbuh 362
 * Big Labyrinthine Building: a huge, labyrinthine, treehouse.
 * Big "Shut Up!": Lizzie in "Operation D.A.T.E.".
 * Bilingual Bonus
 * Numbuh Three's last name, Sanban, loosely translates to "third" in Japanese.
 * Mushi's first name translates to "insect".
 * In "Operation: T.R.I.P.", the Interesting Twins from Beneath the Mountain crash into a poster with the word いたい ("iitaii"), which translates to "it hurts", lampshading their Chew Toy status in the episode.
 * Numbuh One's last name, Uno, is Spanish for "one".
 * Black Bead Eyes: What most of the characters have, however there are a few exceptions.
 * Blasting It Out of Their Hands: Exaggerated in the episode "Operation: V.I.R.U.S."; Numbuh One is confronted by Cree Lincoln and pulls out a handgun, which she shots out of his hand with her Arm Blaster. Then he pulls out seven other guns from various spots on his body which she blasts out one by one. Thus Nigel is left with only... a comb, which Cree also shoots from his hand.
 * Blessed Are the Cheesemakers
 * In "Operation: L.I.C.E.", the giant mutated lice are killed by cheddar.
 * "Operation: T.H.E.-S.H.O.G.U.N." provides a particularly over-the-top example.
 * Bond One-Liner: "Operation: I.N.T.E.R.V.I.E.W.S.": "I've always wondered how [the Delightful Children From Down The Lane] all went to the bathroom together."
 * Book Dumb: Numbuh Four is this, big time.
 * Brains and Brawn: Numbuhs Two and Four.
 * Brainwashed: Double Subversion in "Operation: C.A.M.P.".
 * Brainwashed and Crazy: The Delightful Children From Down The Lane.
 * Brats with Slingshots
 * Brick Joke: Of the "very long time" and "blink and you'll miss it", variety. In "Operation F.L.A.V.O.R.", Numbuh Five tastes the "fourth" flavor of ice cream, but is stopped before she can exclaim what it tastes like. Fast forward to Operation Z.E.R.O. and the briefly says what it is:
 * Not to mention Numbah 4's singing at the ends of the P.O.O.L. and M.O.O.N. operations.
 * Broken Streak
 * In "Operation: C.A.K.E.D.-F.O.U.R.", the Gilligans' Tube-A-Thon losing streak is broken by Tommy. Hoagie would've finished the race as well, had there not been a "Friend or Idol?" Decision.
 * Speaking of the C.A.K.E.D. missions, each one that comes up usually has the KND ruining the Delightfuls' Birthday in some form or another. However on the Sixth one (the title which cleverly omitted the C.A.K.E.D. from it), the Delightfuls manage to get one over on the K.N.D in a delicious irony: without them even knowing it till the end.
 * Burning with Anger: Father is not just Wreathed in Flames, but they increase in intensity when angry.
 * But Not Too Foreign: Numbuh Five (and her sister Cree) are half-French, half African-American. Both of their parents are still Black, though. And their father is a parody of Bill Cosby.
 * Caffeine Bullet Time: "Operation: U.N.D.E.R.C.O.V.E.R." has a Villain of the Week that has Super Speed from consuming large amounts of coffee regularly. When Numbuh Five gets a coffee overdose of her own, she gets temporary Super Speed as well, but notably crashes pretty quickly and realistically.
 * Cain and Abel: Three groups.
 * Numbuh Five and Cree.
 * Numbuh Three and Mushi, to a lesser extent.
 * Not to mention.
 * The Cake Is a Lie: In "Operation: I.N.T.E.R.V.I.E.W.S.", KND scientist Numbuh 74.239 claims he has taken the Delightful Children From Down The Lane's cake and announces a scavenger hunt for it. wins -- only to find out that.
 * Card-Carrying Villain: Nearly all of the villains are this. Supervillain meetings are held regularly. Several lines in the series directly mention this trope, like this gem from "Operation: T.R.I.C.K.Y.":

"Kuki: Toys? I don't want toys... I WANT REVENGE!!"
 * Cerebus Syndrome
 * Cereal Vice Reward: The KND stealing the Delightful Childrens' birthday cake and ruining their birthdays in the "C.A.K.E.D." episodes).
 * Chef of Iron: Granny Stuffem and her creations.
 * Chewing the Scenery: Everyone, at least once. The voice actors really held nothing back.
 * Clingy Jealous Girl: Nigel's girlfriend, Lizzie.
 * Chained Heat: Numbuh One and Chad as part of a subplot of "Operation: T.R.E.A.T.Y.".
 * Children Are Innocent: Subverted, as the KND is Chaotic Good. (Though individuals will go off on their own and do some pretty Chaotic Neutral stuff. This is particularly true of Numbuh Four, but the entire team has fought with their entire Rogues Gallery over a box of cereal.) Though played straight because most of them don't know where babies come from. This is subverted with Numbuh Five, who does know, because her father is a doctor. Plus she mentions she has an older brother who has a few kids.
 * Christmas Episode: "Operation: N.A.U.G.H.T.Y."
 * Closer Than They Appear: The mirror on one vehicle says "Missiles in mirror may be closer than they appear".
 * Colony Drop: In The Movie, they
 * Colour-Coded for Your Convenience / Five-Kid Band: Sector Z
 * Numbuh One/Nigel, "The Hero / The Leader" - Red
 * Numbuh Two/Hoagie, "The Inventor" - Blue
 * Numbuh Three/Kuki, "The Flirt / The Ditz" - Green
 * Numbuh Four/Wally, "The Tough Kid - Orange
 * Numbuh Five/Abby, "The Cool Kid" - Purple
 * Numbuh T/Tommy, "Tagalong Kid"
 * Numbuh Six / Bradley, "The Sixth Ranger"
 * Temporary Numbuh 49/Lizzie, "The Load" - Yellow
 * Combat Tentacles: The giant turnip's in "Operation: T.U.R.N.I.P.".
 * Competence Zone: Anyone 13 or older is a threat to the Kids Next Door, and must have their memories of the organization erased. In this universe, unlike the real one, many teenagers serve as loyal minions for adults (although there are plenty who just view kids as irritants). The show eventually subverted this in the episode "Operation: M.A.U.R.I.C.E.", which revealed that some teenaged KND agents are retained as undercover operatives. Which may or may not be a subtle Shout-Out to the Steve Miller Band.
 * Conspiracy Kitchen Sink: This show is practically built on conspiracies (sometimes literally). Not surprisingly, the KND were even responsible for the fake moon landing.
 * Continuity Creep
 * Continuity Drift: The first season finale, "Operation: G.R.O.W.-U.P.", seems kind of off after viewing later seasons. Instead of getting decommissioned, Nigel just leaves the group and gets a job with his memories intact. It stands to reason that they had no reason to go after him. By the system he was still 10 years and it wouldn't have alerted the decommissioning department. None of his team would report him, either, so as far as anyone outside his team knew, nothing had changed.
 * Continuity Nod: Frequently, such as Numbuh One recognizing A Glitch in the Matrix when he remembered that
 * Contest Winner Cameo: Complete with no spoken lines, and an overly detailed face!
 * Cool Shades: Numbuh One's got 'em.
 * Cowboy Episode
 * "Operation: M.E.S.S.A.G.E."
 * "Operation: N.U.G.G.E.T."
 * Crapsack World: The world under Grandfather's rule. Imagine child labor during the Industrial Era and take it Up to Eleven.
 * What the world normally is. Lets face it, KND is one of the most screwed up worlds.
 * Credits Gag: The production team is given military-inspired job titles.
 * Creepy Child: Creepy children: The Delightful Children from Down the Lane, who all speak and even move in unison.
 * Subverted in one episode where one of the DCFDTL appears to break free from the group to act as a spy for the K.N.D. Double Subverted when
 * Creepy Monotone: See directly above. The Delightfuls subvert this a few times, though, most notably in "Operation: G.R.O.W.-U.P.", mainly to highlight just how scary an angry Father was.
 * Crossover: "The Grim Adventures of the Kids Next Door"
 * Crouching Moron, Hidden Badass: Sector V, initially. Being the main characters of the show, it's implied at first that they're the only Kids Next Door operatives; however, when the organization is shown to have teams across the globe, Sector V is shown to be one of, if not the best around.
 * Dark Horse Victory: "Your new fourth grade president is.... EGBERT EGGLESTON!"
 * A Day in the Limelight
 * Demon Head: Numbuh Three often displays this.
 * A Day in the Limelight
 * Demon Head: Numbuh Three often displays this.

{{quote|"She. Just. Owes. Me. A. Quarter."}} {{quote|Numbuh One: The Splinter cell? I thought they were just a bunch of sci-fi nerds who watch that dumb doctor time-space-continuim show.
 * Disguised in Drag: Numbuh Four becomes Numbuh 4-30teen-7 for "Operation: S.L.U.M.B.E.R.".
 * Disney Villain Death: The Delightful Children and Father both fall victim to this in the Grand Finale, though the latter case is subverted.
 * Distant Finale
 * Does Not Like Boys: Numbuh 86
 * Subverted in a comic where she's accidentally decommissioned, and starts to smooch every boy on Moonbase. Hilarity Ensues.  This subversion carries Unfortunate Implications, as it is implied that whatever made her hate boys happened after she joined the KND.
 * Dope Slap: Numbuh Five dope-slaps Numbuh Four after the latter eats some Coco Nut Logs despite being allergic to coconut.
 * Drinking Contest: The Pirates of the Caribbean parody episode replaces the alcohol with mugs and sacks of pure sugar.
 * Driven to Suicide: Both unintentional and subverted with
 * Dude, Where's My Reward?: Tommy Gilligan saves the organization, but doesn't get re-enlisted due to security measures.
 * Eleventy Buh-million
 * Embarrassing First Name: Numbuh 86's real name is Fanny. The joke has some Unfortunate Implications when you realize what the Scottish-accented Fanny's name means in her homeland... Further implications abound when you take into account the fact that she's a complete FemiNazi.
 * Epic Fail: In "Operation: D.A.D.D.Y.", Mr. Boss intends to save money by cutting the hair of his own children instead of taking to them to a barber. The resulting haircut on his son is impossibly bad.
 * Even Bad Men Love Their Mamas: Subverted by Black John Licorice; according to Stickybeard's sea shanty, he would even steal candy from his own mother.
 * Even Evil Has Standards: Plenty of villains in the series have shown to do this: for example, Stickybeard saves Sector V from the giant white asparagus because while he steals candy from kids, he won't allow anyone to be forced to eat asparagus.
 * Everything's Even Worse with Sharks: Especially when they can get a literal kid burger via fast food drive-thrus.
 * Expy: Moosk in "Operation: K.N.O.T." is obviously an Expy of Baldur's Gate's Minsk, right down to both characters being voiced by Jim Cummings.
 * Everything's Better with Rainbow Monkeys
 * Face Heel Turn
 * Cree and Chad after they turned 13.
 * Also every other decommissioned KND operative.
 * This actually applies to kid characters too; in "Operation: S.L.U.M.B.E.R.".
 * "Operation: A.R.C.T.I.C." has (the group didn't know this till the end of the episode and even then found out they were targeting the wrong guy).
 * "Operation: T.I.E." (which, ironically has a grown-up protagonist).
 * at the end of "Operation: P.R.E.S.I.D.E.N.T.".
 * The Faceless: Played with, for all of Sector V's parents. Numbuh Two and Numbuh Three's parents are Aversions. Numbuh One's dad is played straight and then subverted in his first appearance. Numbuh Four's parents are subverted and played straight when wanted, and Numbuh Five's parents play it straight.
 * Face Palm: Frequent, mostly for Numbuh One and Numbuh Five.
 * Fake Defector: The teenager in "Operation: F.U.G.I.T.I.V.E." is often mistaken for one.
 * False Start: Numbuh Four's crush on Numbuh Three. This quickly becomes a Running Gag.
 * Fantastic Voyage: "Operation: S.P.R.O.U.T."
 * Fat Sweaty Southerner in a White Suit: Jimmy Nixon McGarfield, the Fourth Grade President-for-Life, is a tween example. He starts out with the typical white suit,.
 * Five-Token Band: One Brit (with a Spanish name), one American Jew, one Japanese, one Australian, and one half-French African-American. The extended cast is even more varied, though most of the stories take place in the U.S.
 * Flanderization: The Delightful Children from Down the Lane have always spoken and moved in unison, but in later episodes this is taken even further as they are practically considered a single entity, from wearing a single costume large enough for them to all fit in to having all five of them simultaneously date Numbuh Three.
 * Flash Back: Used to open "Operation: M.A.U.R.I.C.E.", "Operation: H.O.M.E.", "Operation: C.A.K.E.D.-F.I.V.E." and "Operation: T.R.E.A.T.Y.".
 * Foreshadowing: In "Operation: P.O.O.L.", . In Operation: Z.E.R.O.,
 * Four-Fingered Hands: Averted. And to a degree that makes it clear why this trope is usually played straight.
 * Friendly Enemy: "Operation: E.N.G.L.A.N.D." shows us that Sector E and the "Rowdy Hooligans from Across the Square" put aside their differences to relax and tell jokes. Numbuh One questions why they don't fight each other, and they respond that fighting over a Rainbow Monkey library book is something that Americans would do.
 * Frothy Mugs of Water: Parodied in an episode where root beer is treated like actual beer, complete with references to U.S. Prohibition. In fact, all soda is pretty much treated like alcohol in the KND universe. And then there was the ep where Numbuh Five and Stickybeard had a drinking contest, by downing huge frothy mugs of pure sugar.
 * Fun with Acronyms: Goes hand in hand with Idiosyncratic Episode Naming, but the various machines the kids use also have acronym names.
 * And in the Mirror Universe episode, the acronyms are even reversed -- the counterpart to the Kids Next Door (KND) are the Destructively Nefarious Kids (DNK) and the counterpart to the Delightful Children From Down The Lane (DCFDTL) are the Little Traitor Dudes For Children's Defense (LTDFCD).
 * Only one early episode didn't have fun with them -- "No P in the OOL".
 * Gang of Critters: Rainbow Monkeys
 * Gender Bender: "Operation: F.U.T.U.R.E."
 * Genius Ditz: Numbuh Two
 * Genki Girl: Numbuh Three. "Genki" is even her mother's name (which is rather a subversion as Genki is anything but).
 * Genre Savvy: Father isn't one of the toughest villains for nothing. He tries ageing Number One but Number One still fights against him. This plays into his next big plot realizing the K.N.D. would probably still fight against him even as adults he transforms them into animals instead. He's defeated by Tommy making him a K.N.D. operative and transforming him into an animal due to his own device. He uses his involuntary induction into the K.N.D. to become supreme leader. And that's just some of the most notable of his Genre Savvy moments.
 * Dangerously Genre Savvy: Grandfather. And HOW. He practically destroys the K.N.D. and succeeds in retaking control of the world like before but worse. Yet instead of kicking up his heels like most would do and relaxing with some tapioca he then focuses his attention on destroying a last Hope Spot, the book of K.N.D. which led to his defeat the last time. Even when one of his own sons show some resistance to their family's evil ways he decides to zombify him instead of just leaving him be.
 * And it was by restoring Grandfather's memory Father showed another moment of Genre Savvy. To steal the memory-restoring device from the museum, he sent two groups of villains: one to the museum and one to assault the moonbase as a distraction. Almost all KND operatives believed the museum raid to be the distraction. Later, when Father assembled the other villains so they'd see him using the device on Grandfather, he not only expected Numbuh One to show up but also wanted it to happen. It turns out the device couldn't be activated without boogers from an active KND operative and, since Father's and the Delightful Children's involutary inductions were already over, he needed to take it from somebody.
 * Getting Crap Past the Radar: Enough to deserve its own subpage.
 * Girls Have Cooties: "Operation: O.U.T.B.R.E.A.K."; Sector V is sent on a mission to decontaminate the organization's underwater research center from the much-feared Coojatisnal Octo Oogie Terta Infecto Epi Streptacaucus.
 * Girls Love Stuffed Animals: And they absolutely adore Rainbow Monkeys.
 * A Glitch in the Matrix: Numbuh One finds one when he notices that Numbuh Four is at a pool party despite being unable to swim.
 * Gosh Dang It to Heck: Numbuh Four's constant use of the word crud.
 * Guns Akimbo
 * Grand Finale
 * Growing Up Sucks: Oh so very much.
 * Half-Identical Twins: The Interesting Twins from Beneath the Mountain.
 * Hammerspace: Where the KND store most of their cool gadgets.
 * There is an episode where Numbuh One pulls out at least eight weapons one at a time from nowhere, only to be blasted by Cree.
 * And in "Operation: E.N.G.L.A.N.D.", Numbuh One gives the airport security a nightmare with the mountain of junk on his person.
 * Harmless Villain: The Toilenator. Even at his best, when he actually bypasses the treehouse's security systems and take control of Sector V, he STILL SCREWS UP a much larger plan that Mr. Boss and the other villains were planning beforehand.. In fact, he does that twice.
 * Hates Being Touched: The Delightful Children from Down the Lane, Father, and Numbuh 363.
 * Heel Face Mole: "Operation: U.N.D.E.R.C.O.V.E.R.", where one of the Delightful Children joins the KND.
 * Heroes Unlimited: What, you thought the main charaters were the only ones?
 * Hidden Eyes: Each operative from Sector V has hidden eyes of different varieties. Numbuh One has Cool Shades, Numbuh Two has goggles that do nothing, Numbuh Three has Eyes Always Shut, Numbuh Four has Blinding Bangs, and Numbuh Five has a Nice Hat covering her top face.
 * High on Catnip: Catnip causes the Cat Lady's cats to have a sudden dance party.
 * Hive Mind: The Delightful Children From Down The Lane, who seem to represent conformity personified; although later episodes make it clear that they're not a literal case of one mind shared by five bodies, they always speak and act in unison. It's kind of telling that in "Operation: R.E.P.O.R.T.," Numbuh Two's side of the story is the only one that depicts them with five separate bodies rather than five heads on a single two-armed body.
 * Hoist by His Own Petard: A few villains are defeated in this fashion.
 * For example,.
 * Homage: Many separate occasions; their parodies of Star Wars border on ripping it off and The Matrix homages don't even pretend otherwise.
 * "Operation N.A.U.G.H.T.Y.", the Christmas Episode, is presented in American Comic Format. It includes a group of Santa helpers which Expies the X-Men, a group of enemies that Expies the Fantastic Four, a Machine that resambles "the Cerebro" and X-Men 3''.
 * Hourglass Plot: "Operation: T.R.E.A.T.Y." between Numbuh One and Chad. To hammer the point home, the dominant color of their clothing in the Flash Back (Blue for One, Red for Chad) is the opposite of their clothing in the present (Red for One, Blue for Chad) {{spoiler|and Numbuh One beats Chad by using the same technique Chad beat him with in the flashback.}}
 * Humongous Mecha: H.I.P.P.Y.-H.O.P., and many, many others, made of everything from lawn chairs to treehouses to cats.
 * Hunting the Most Dangerous Game: "Operation: S.A.F.A.R.I."
 * Hypno Trinket: The Boyfriend Helmet.
 * Hypocritical Humor: In one episode Lizzie criticizes Nigel about his weight when she's much fatter than he is.
 * I Ate What?: Features in "Operation: P.I.N.K.E.Y.E.", where Numbuh Two is eating Nurse Claiborne's crumbles as he's investigating the mystery epidemic of pinkeye going around the school. Once it gets out that it is Claiborne herself who was the one infecting the students with pinkeye, it also becomes apparent that she was using eye crust for her crumbles, making Numbuh Two gag at the very fact that he was eating them. However, at the very end, he goes back to eating them. However, Numbuh Two may have second thoughts after finding out that the filling of the crumbles is {{spoiler|mucus.}}
 * Idiosyncratic Episode Naming: "Operation S.O.M.E.T.H.I.N.G. -- String Of Meticulously Encoded Text Handily Includes Naming Gag"
 * I Can't Believe It's Not Heroin!
 * Hoagie (Numbuh Two) was so addicted to chocolate sauce that he used to bathe in it. Eventually he had to sign up to Chocoholics Anonymous.
 * In the KND universe, candy is the number one source of happiness. If a child is kept from candy too long or is given a non-candy substitute, they go through an exaggerated form of withdrawal.
 * In "Operation: L.I.C.O.R.I.C.E.", Black John Licorice challenges Abigail (Numbuh Five) to gulping down mugs of sugar. Numbuh Five's sugar level becomes so high that her eyes widen and she begins to shake violently.
 * Idiosyncratic Wipes: Examples found here.
 * In Medias Res: Many per episode.
 * Incredibly Lame Pun
 * Numbuh Two is the Patron Saint of this trope. A real Pungeon Master.
 * Apparently, in one of the Indiana Jones parodies, Numbuh Five is tested about the Ice Cream flavor of the Day. Her answer? Sundae. The Ice Cream Gods must believe puns are a form of logic, because she is allowed access after she answered.
 * Indy Hat Roll: One of the many trademark Indy moves executed by Numbuh Five. Complete with reaching back for her fallen hat in "Operation: L.I.C.E." {{spoiler|-- although this time it's a trap from the DCFDTL: this is not her hat}}.
 * In Medias Res: Many an episode.
 * Insulted Awake: Happens to Nigel Uno a lot.
 * Instant Armor: Evil teenagers use Battle Ready Armor (or B.R.A.s) to fight the KND.
 * Instant Plunder, Just Add Pirates: Candy pirates.
 * I Was Told There Would Be Cake: Seven of the episodes feature the KND trying to take the cake from the Delightful Children from Down the Lane, who refuse to share it with anyone. To make it worse, said DCFDTL brag and boast about it, giving the KND justification. The cakes seem to vary, in both appearance and what happens to it (as in destroyed).
 * To start, the first one (used in "Operation: C.A.K.E.D." is a normal one. It is {{spoiler|destroyed by accident}}.
 * The second one ("Operation: C.A.K.E.D.-T.W.O.") is semi-sentient, and attacks the KND. It is {{spoiler|destroyed and split into a ton of drops when Lizzie flew in to save Numbuh One. Everyone but the DCFDTL got a bit}}.
 * The third cake ("Operation: C.A.K.E.D.-T.H.R.E.E.") is a normal one, but bigger than the last one. It isn't destroyed per se, but {{spoiler|it is soiled by Numbuh One's pet chicks doing their business, thus ruining the KND's mission}}. However, the DCFDTL ate it!
 * The fourth cake ("Operation: C.A.K.E.D.-F.O.U.R.") {{spoiler|isn't really made, but it is a good thing, this time, because this year's competition is a trap by Father to mix in the kid competitors into the cake. Ruined by Numbuh Two, however, spilling the cake batter, and ruining his chances at winning the competition this year.}}
 * The fifth one... ("Operation: C.A.K.E.D.-F.I.V.E.") {{spoiler|well, three words. Death Star-sized. It functions both as an ice cream cake and as a battle station that would destroy all the ice cream on Earth. It is destroyed when one of the ships is shot down, cutting the cake in half.}}
 * The sixth one ("Operation: S.I.X.") is a doozy, {{spoiler|because it pulls a delicious irony -- the KND delivers the cake to them.}} Unknown if the KND retaliates or if the cake is destroyed. Probably not destroyed, because in "Operation: I.N.T.E.R.V.I.E.W.S.", {{spoiler|Numbuh Two said that they brought the cake back in one piece... once, but that did not stop Numbuh 74.329 from Pulling Sector V out of the Cake stealing mission and giving the case to Sector W.}}
 * The seventh one ("Operation: I.N.T.E.R.V.I.E.W.S.") {{spoiler|is almost taken by Sector V, but the DCFDTL gets away. Unfortunately, it is stolen by another operative, who put up a scavenger hunt to see who gets the cake. Numbuh One wins, but it turns out it is a cupcake. It is destroyed when the operative who stole it ate it. It turns out the scavenger hunt was a test for Numbuh One to see if he was ready to join the Galactic KND.}}
 * Jerkass
 * Numbuh 86 can be one sometimes (to boys at least), but we can also count her as a Jerk with a Heart of Gold.
 * Numbuh 363, however, is notably lacking in the "heart of gold" department.
 * Kangaroo Court: {{spoiler|Parodied to a dramatic degree in "Operation: E.L.E.C.T.I.O.N.S.", as the DCFDTL are the judges. No witnesses, no jury, and a defense that didn't get a single shot at defending Numbuh One.}}
 * Kids Versus Adults: And how.
 * Lady Land: "Operation: F.U.T.U.R.E."
 * Latex Perfection: Pretty much the game plan for The Interesting Twins from Beneath the Mountain. They're able to change disguises when needed, without anyone knowing. They get foiled, however, because the Japanese KND and Sector V know about it and aren't fooled. {{spoiler|In the first episode they appear in, it turns out that the KND foil them with a Batman Gambit by disguising as Numbuh Three's grandmother, by playing the very same trope. Same goes to the Japanese KND, who also played this trope to ALSO foil the Interesting Twins' plan.}}
 * Large Ham: Grandfather IS one.
 * Lethal Chef
 * Villain Grandma Stuffem has this as a literal power.
 * Lizzie is a more usual example of the trope. When Nigel is sick, she makes him her special "Chicken banana-fritter soup". With "extra curly fries". Nigel uses the soup as an explosive later on. Her pie in "Operation: H.O.L.I.D.A.Y." is so gross, it makes Numbuh Two pass out when he accidentally swallows just a slice.
 * Little Miss Badass: Played strait with Numbuh Three and possible Numbuh 86, but subverted with more or less all the other girls in the Kids Next Door (especially Numbuh Five and Numbuh 362) who for the most part are, well, still badass, but don't seem to be intentionally intended to be cute or especially effeminate in any way. Instead they tend to have some what androgynous dress senses (really especially Numbuh Five and Numbuh 362) and personalities to match.
 * Limited Wardrobe: Subverted with further seasons as the team gets a variety of gear in addition to pajamas and swimsuits. Numbuh Three has the most varied wardrobe.
 * Loads and Loads of Characters: After Season 3 and 4 start rolling around, there is a lot of minor operatives and villains to keep track of.
 * Lotus Eater Machine: Chester's headband. Consistent with the series, it sends Nigel to a fake Destiny Islands, where an Expy of Kairi greets him and shows him around the paradise they have without adults. Nigel grows suspicious, but his "comrades" reassure him that he's just being paranoid, until he remembers that Numbuh 4 can't swim, but he's doing the backstroke in a pool of soda. {{spoiler|In the end, Nigel puts Chester in his own headband, convincing him he'd defeated him and was being praised by the other villains...that is, until Numbuh 4 turns it to its nightmare setting.}}
 * Loved I Not Honor More: Comes up for Nigel and Lizzie in "Operation: G.I.R.L.F.R.I.E.N.D.".
 * Love Makes You Evil: Jimmy McGarfield in "Operation: S.N.O.W.I.N.G.".
 * Lower Deck Episode: "Operation: T.R.A.I.N.I.N.G."
 * Luke, I Am Your Father: Nigel finding out {{spoiler|his father, uncle and grandfather are Numbuh Zero, Father, and Grandfather respectively}} in the movie. Nice hat trick.
 * Added bonus reveal from the CN comic book: {{spoiler|The Toilenator is Wally's uncle.}} The story was written by Mr. Warburton, it must be canon.
 * Made of Diamond: Grandfather. They {{spoiler|crash a moonbase on him and he dusts it off like it was nothing!}}
 * Mad Scientist
 * Mushi Sanban in "Operation: S.P.A.N.K.E.N.S.T.I.N.E.".
 * Basically a lot of KND Operatives.
 * And several villains too, like Professor XXX-L or Chester.
 * Magic Skirt: Kuki's wedding dress in "Operation: B.E.A.C.H.", when King Sandy hangs her upside down by her feet.
 * Make-Out Point: Doubly subverted. Although there is implication in another episode that The Point does live up to its name.
 * The Man Behind the Man: Father
 * Meaningful Name
 * All of Sector V:
 * Numbuh One is Nigel Uno -- "uno" is Spanish for "one", since he is the leader.
 * Numbuh Two is Hoagie P. Gilligan, Jr. -- appropriately enough, a twofer reference: Bob Denver's character Gilligan was second-in-command of the S.S. Minnow on Gilligans Island; the Jr. generational suffix means that Numbuh Two is the second male in the Gilligan family to be named "Hoagie P. Gilligan".
 * Numbuh Three is Kuki Sanban -- "sanban" is Japanese for "number three", and "Kuki" is a reference to Numbuh Three being a Cloudcuckoolander.
 * Numbuh Four is Wallabee Beetles -- there were four members of The Beatles, even though Numbuh Four is Australian (as implied by his accent and the name Wallabee [wallaby]), not from Liverpool; plus, the number four is considered bad luck in Chinese culture (similar to the number 13 in Western culture), and Numbuh Four has the worst luck of all the Sector V operatives.
 * Numbuh Five is Abigail Lincoln -- has the same initials as U.S. President Abraham Lincoln, who is on the five-dollar bill in American currency.
 * Also, Numbuh Three's father is named Kani -- Japanese for "crab" -- which is pretty much his entire personality, and Numbuh Three has a little sister named Mushi, which is Japanese for "bug" and matches her irritating personality.
 * Heck, pretty much all the Operatives' Codenames are a pun on their profession.
 * Numbuh 30C, whose name was a clue as to the villain of the episode. {{spoiler|It's 86 degrees F}}
 * Numbuh 86, whose original job in her debut episode was decommissioning -- or 86ing -- teenaged operatives; plus, her real name is Fanny (short for Frances), seeing as she is an ass (or a cunt, if you want to use the vulgar definition of "fanny" as heard in the United Kingdom).
 * Numbuh Change-for-a-20 runs the KND moonbase cafeteria cash register.
 * Father's real name is Benedict, as in Benedict Arnold... he's not really a traitor, though, so much as {{spoiler|a coward who didn't want to stand up to his own father, Grandfather, and ended up siding with him out of fear of retribution.}}
 * Even Tommy Gilligan, who is a parody of Sixth Rangers in the series, shares his first name with the Trope Namer, Tommy Oliver, the Green Mighty Morphin Power Ranger.
 * Medium Blending: "Operation: I.N.T.E.R.V.I.E.W.S.", where the interviews with the adult Sector V is done in live-action.
 * Mirror Universe: "Operation P.O.O.L."
 * Misplaced Sorrow: Numbah Three is about to be married to King Sandy, a kid pretending to be a king. Numbah Four claims that the only reason he wanted to rescue her isn't because he's jealous, but because she owed him a quarter.
 * The Mole: In "Operation: M.A.U.R.I.C.E.", {{spoiler|Maurice -- a mole himself -- reveals that a few special and loyal operatives still help the KND after their "decommissioning" and into their teen and adult years. Ironically, Chad was also one of these and he doesn't reveal it until the penultimate episode of the series.}}
 * Monster Progenitor: Miss Thomson, was the Queen were-dog responsible for turning her student into were-dogs.
 * Mood Whiplash: Especially the later episodes.
 * The Movie: Operation: Z.E.R.O.
 * Musical Episode
 * "Operation: L.O.V.E.", doubling as a spoof of West Side Story.
 * Also "Operation: N.U.G.G.E.T." may count.
 * My Little Panzer: The Boyfriend Helmet.
 * Naked People Are Funny
 * Narm
 * In-universe example: Numbuh Four busts out laughing in "Operation: F.O.U.N.T.A.I.N." {{spoiler|when Leona threatens to kill him and his friends, because of her horrible lisp.}}
 * Otherwise, this becomes egregious in "Operation: M.A.U.R.I.C.E.", with Numbuh Five having chicken pox.
 * Naked People Are Funny
 * Naughty Is Good: The perfectly well-behaved Delightful Children from Down the Lane are villains; the heroes are rebellious, mischievous, and disobedient but fight for the rights of kids everywhere.
 * Negated Moment of Awesome: The Cyclocannon. Right after Sector V finishes morphing their bikes and counting down from five, Tommy shows up and does what he does best, crashing right through it with his bike and destroying it.
 * Never Bareheaded: One of the Delighful Children never takes off his football helmet.
 * Nice Job Breaking It, Hero
 * One by both Gilligan brothers. Early on, Tommy sticks one of Father's boogers in the decommisioning machine to count him as a member of the KND and turn his transforming ray on him. Later, during a tag game to decide who will take 362's place, {{spoiler|Numbuh Two is rushing to find somebody to tag in the last few seconds, and he tags the first person he finds on the other side of the door he opens. Tag, Father, you're it!}}
 * The end of "No P in the Ool", where Numbuh One tries to hijack Mr. Fink and Mr. Fib's chair machine, only to accidently acticate the drill on it, which subsequently drains the pool, meaning neither side wins.
 * Night of the Living Mooks
 * "Operation: U.N.C.O.O.L.", with pasty-white-skinned nerd zombies.
 * This is practically Grandfather's MO.
 * Noble Shoplifter: This happens when Number 2 has to go to the grocery store, but it's already closed. He picks up the items he needs and leaves money behind, but still gets accused of trying to steal.
 * No Celebrities Were Harmed
 * Dr. Lincoln is an Expy of Bill Cosby.
 * Robin Food's sidekick is pretty much Sammy Davis Jr.
 * Count Spankulot is modeled after Bela Lugosi's Dracula.
 * Numbuh 10-speed, leader of the KND Central Bike Hub, is a kid version of Lance Armstrong.
 * No Dialogue Episode: "Operation: T.H.E.-F.L.Y."
 * Non-Lethal Warfare
 * Not Brainwashed: "Operation: C.O.L.L.E.G.E."
 * Not Hyperbole: When Cree says she'd turn the treehouse upside down, she means it.
 * Obfuscating Stupidity: {{spoiler|Numbuh Three, according to The Other Wiki.}}
 * Oddly Visible Eyebrows
 * Official Couple: {{spoiler|3×4, 2×5 (maybe), and Nigel×Lizzie temporarily}}.
 * One-Letter Name: Numbuh T sort of follows this trope. But T is NOT a number! There is no Numbuh T, only The Tommy!
 * Operation: B.L.A.N.K.: Complete with acronyms. Below is an example.
 * "Bland Lame Acronyms Now Kool"
 * Our Werebeasts Are Different: Our Werepoodles Eat Homework.
 * Our Vampires Are Different: Count Spankulot is a vampire who spanks "naughty" children and can turn others into "spank-happy" vampires by spanking them gloveless.
 * Paper-Thin Disguise: Numbuh 4-30teen-7. Surprisingly no clear sign of being subverted.
 * Platonic Life Partners: Numbuhs One and Five. Justified in that the former is Sector V's head and the latter is his second-in-command/right-hand woman. To a lesser extent, the members of Sector V who aren't romantically interlinked to each other.
 * Portal Pool: To the Mirror Universe.
 * Power Limiter: Count Spankulot can turn others into "spank-happy vampires" by spanking them gloveless.
 * Power-Up Food: One episode has a villain named Cuppa Joe, a rig overseer who gains Super Speed from drinking excessive amounts of coffee.
 * Punctuated for Emphasis: Wally's response to his crush on Kuki:
 * Pungeon Master: Numbuh Two
 * Punny Name
 * Punk Punk: One of the codifiers of Kid Punk.
 * Raise Him Right This Time: The one-off villain Mr. B, after being hit by his own "babyfier ray".
 * Really Seven Hundred Years Old: {{spoiler|Leaky Leona, who turns out to have been using the Fountain of Youth to maintain her 10-year-old form for the past 300 years.}}
 * Rebus Bubble: 2 + 2 = Pizza
 * Red Oni, Blue Oni: Two groups.
 * Numbahs One and Five.
 * Numbahs Four and Two.
 * Ridiculously Cute Critter: Bradley (a.k.a. Numbuh Six) and the treehouse hamsters.
 * Rule of Cool: This show thrives on it.
 * Safety Worst: Parodies by exaggeration in "Operation: S.A.F.E.T.Y.".
 * Samus Is a Girl: {{spoiler|Henrich when we finally learn why he was so peeved at Numbuh Five.}}
 * Sassy Black Woman: Numbuh 5 and her sister, Cree.
 * Savvy Guy, Energetic Girl: Numbahs 84 ("Tactical Yoyo Specialist") and 83 ("Soda, Snacks, and Treats Officer").
 * Second-Person Attack: At the end of "Operation: S.P.A.C.E.", Numbuh 1 points his mustard gun toward one of the characters, and his blast fills the entire screen and fades to black.
 * Serious Business: Don't get us started....rainbow monkies and cake and card collections.....
 * Set Right What Once Went Wrong: "Operation: F.U.T.U.R.E."
 * Shout-Out: Loads and loads of these.
 * Character-specific:
 * The antagonists, The Delightful Children from Down the Lane, seem to be based on the antagonists in co-creator Mo Willem's 1996 Ka Blam, sketch, The Off-Beats, known as "The Populars".
 * Father appears to be based off of J. R. "Bob" Dobbs.
 * Numbuh 86 is possibly a Shout-Out to Rosa Klebb, another hot-tempered, red-headed, boy-hating operative with a grating accent and a grudge against a British agent.
 * The Tommy's costume (wide-brimmed hat, mask and cape), hammy poses and catch phrase ("I am The Tommy!") reminds of another animated superhero. Probably also a shout-out to The Shadow.
 * Two of the England KND members are a Shout-Out to the The Avengers and Doctor Who respectively.
 * Numbuh 11-Teen is based off of Jane Goodall
 * Mr. Wink and Mr. Fibb are based of of Mr Kidd and Mr. Wint
 * I was hungry (slap), I was thirsty (slap), I was hungry (slap), I was thirsty (slap),..., I was hungry and thirsty.
 * The Delightful Children are turned into sheep in one episode. The middle one resembles Sheep from Sheep in The Big City. Also, in "T.H.E.-F.L.Y.", one of the stuffed animals shown in Numbuh 3's room is Sheep.
 * Dexter appears as a balloon in a Zombie Apocalypse episode.
 * "Operation: H.O.M.E." gives us the origins of Rainbow Monkey Cereal. {{spoiler|"IT'S MADE FROM RAINBOW MONKEYS!"}}
 * Operation R.E.P.O.R.T. does five parodies in one episode.
 * Numbuh Four's version of "Operation: R.E.P.O.R.T." is a huge one to Dragonball Z. At one point he blows a chewing gum bubble into his hands to make what looks like a Chewing Gum Kamehameha.
 * When the Dodgeball Wizard says that he's not a magician, Numbuh Four's dad says, "All right, you're an illusionist then!"
 * In "Operation: E.N.G.L.A.N.D.", one of the British KND operatives {{spoiler|(actually one of the Rowdy Hooligans from Across the Square)}} repeatedly says to Numbuh One "Nudge-nudge, wink-wink, say-no-more, say-no-more!"
 * Ash Ketchum makes an appearence for one second in a crowd scene. Yes, that one. Yugi, too.
 * Numbuh One: "By your command, Mr. President." {{spoiler|The president is a robot duplicate.}}
 * When a baby makes a hole in a locked door to get to Numbuhs One and Five, he yells, "Heeeere's Jackson!"
 * "Operation P.L.A.N.E.T." features a planet of Rainbow Monkeys similar to the first Planet of the Apes.
 * One very direct Shout-Out in "Operation G.I.R.L.F.R.I.E.N.D.":

Numbuh 362: Not them... and that show's awesome, by the way. }} {{quote|Chad: Surprised to see me? Numbuh Three: Yeah, surprised to see you wearing a bra! (she, Numbuh 12 and 23 laugh) Chad: It's not a bra! It's a Battle Ready Armor! For disguises and stuff.
 * Numbuh One's two-colored glasses in "Operation: L.O.V.E." make him look like Spider Jerusalem from Transmetropolitan.
 * The Christmas special was pretty much a parody of the "Dark Phoenix Saga" from X-Men.
 * And how many kids would have realized that the dude who waves from the pear tree at the end of the "Twelve Days of Christmas" attack in the Christmas Episode was Keith Partridge?
 * "Operation F.U.T.U.R.E. gives us the line, "More tea, Mrs. Nesbitt?"
 * The head of security at the KND Deep Sea Science Lab is Numbuh Twenty Thousand.
 * The island in Chester's headband is a subtle reference to the Destiny Islands. The design looks nothing like the Destiny Islands, but the entire island is a playground with no adults, and Nigel is greeted by a Kairi expy.
 * The Spinach Inquisition are a direct homage to Mel Brooks' History of the World Part One and a sketch in Monty Python's Flying Circus.
 * Smelly Skunk: Numbuh Six, otherwise known as Bradley, is a skunk, and the first non-human Operative in the series. His spray is actually a plot device, as it negates Chester's mind control. His real parents also show up and play the trope straight.
 * Spank the Cutie: Count Spankulot. Do we need to say more?
 * Special Edition Title: "Operation N.A.U.G.H.T.Y.", with the normally-white background turned green, snow falling over the titles, and the title decorated by Christmas lights.(see here). That episode also had a teaser. Only "Operation: E.N.D.", "Operation: S.N.O.W.I.N.G." and "Operation: K.N.O.T." had a Cold Opening before this, and those were much shorter than the one in "Operation: N.A.U.G.H.T.Y.".
 * Slippery Swimsuit: Numbuh One loses his trunks, resulting in an avalanche of jokes about how big his butt is.
 * The Speechless: Numbuh Five was originally going to be one of these.
 * Stalker with a Crush: King Sandy
 * Stealth Pun: When Father is turning KND operatives into animals Numbuh 86 is turned into a dog. Get it? Because she's a bitch! Or because she was already a "scottie" before being turned into a scottie. Although she looks more like an Irish Setter.
 * Stepford Smiler: The Delightful Children from Down the Lane
 * Story Arc: Since there's a lot of them in the series, there's a lot of continunity involved.
 * Season 1: "Operation: I.-S.C.R.E.A.M.", "Operation: T.U.R.N.I.P", "Operation: T.H.E.-F.L.Y", and "Operation: C.A.B.L.E.-T.V." contain elements that are brought back in the season finale "Operation: G.R.O.W.-U.P.".
 * Seasons 1 & 2: "Operation: T.O.M.M.Y", "Operation: C.H.A.D" "Operation: S.U.P.P.O.R.T.", "Operation: O.O.M.P.P.A.H." "Operation: K.I.S.S.", "Operation: F.U.G.I.T.I.V.E.", and "Operation: S.P.A.C.E." set up a story that is concluded in "Operation: E.N.D.".
 * Seasons 2 & 3: "Operation: F.U.G.I.T.I.V.E.", "Operation: E.N.D.", "Operation: T.R.A.I.N.I.N.G.", "Operation: S.L.U.M.B.E.R.", and a game in the Cartoon Network website set up "Operation: G.R.A.D.U.A.T.E.S.".
 * Seasons 3 & 4: "Operation: R.O.B.B.E.R.S.", "Operation: P.R.E.S.I.D.E.N.T.", and "Operation: S.N.O.W.I.N.G." set up "Operation: E.L.E.C.T.I.O.N.S.".
 * Seasons 3, 5, & 6: "Operation: G.R.A.D.U.A.T.E.S", "Operation: I.T.", and "Operation: E.N.G.L.A.N.D." set up Operation: Z.E.R.O..
 * Entire Series: "Operation: C.A.K.E.D.", "Operation: C.A.K.E.D.-T.W.O.", "Operation: C.A.K.E.D.-T.H.R.E.E.", "Operation: C.A.K.E.D.-F.O.U.R", Operation:C.A.K.E.D.-F.I.V.E., "Operation: W.H.I.T.E.H.O.U.S.E.", "Operation: M.E.S.S.A.G.E.", "Operation: S.I.X" "Operation: G.I.R.L.F.R.I.E.N.D.", "Operation: A.M.I.S.H.", and "Operation: T.R.E.A.T.Y." set up the Grand Finale: "Operation: I.N.T.E.R.V.I.E.W.S.".
 * Seasons 2, 3, 4, 5, & 6: "Operation: F.L.A.V.O.R", "Operation: J.E.W.E.L.S.", "Operation: R.A.B.B.I.T.", "Operation: C.H.O.C.O.L.A.T.E.", and "Operation: L.I.C.O.R.I.C.E." set up "Operation: C.A.R.A.M.E.L.", which explains the "Guatemala Incident" in detail. {{spoiler|Turns out Heinrich was a girl prior to it.}}
 * Strange Minds Think Alike
 * A literal example is used with the above Creepy Children.
 * Numbuhs One and Two, having no clue what bras are, use a backronym generator on the word, and eventually conclude that it stands for "Battle Ready Armor" and is a secret Teenager armor device. After some embarrassing hijinx, The Stinger shows us that that is indeed what the Teenagers are using bras for (yes, even the boys). They even use the same backronym.
 * Straw Feminist: Numbuh 86 again, though her attitude doesn't win her any points with the female members either.
 * Suddenly Fluent in Gibberish: In an episode, the kids are trying to save babies at a hospital. Numbuh Three, The Ditz, reveals that "I speak baby," and indeed she does.
 * Sunglasses At Night: Numbuh One mainly, but sometimes other members of the KND as well.
 * Suspiciously Similar Song: The two songs by GWAR that are featured in "Operation: F.O.O.D.F.I.T.E."
 * Swiss Cheese Security: Sector V's Treehouse, unfortunately.
 * Take That: This whole show is a massive Take That towards adulthood. Ironically, this show was made by adults.
 * Temporal Paradox: Again, "Operation: F.U.T.U.R.E."
 * Teen Superspy: Although, strictly speaking, they are tween superspies.
 * Theme Naming
 * Thick Line Animation: Season 1 episodes.
 * Third Person Person: Numbuh Five says she makes referring to herself in the third person cool!
 * Thirteen Is Unlucky: Numbuh 13 is very unlucky, so unlucky that he's spent his entire career being foisted from one team to another because misfortune always befalls his new comrades.
 * This Cannot Be!: "But that's un-possible!"
 * This Is a Drill: The ending of "No P in the Ool".
 * Time Passes Montage
 * "Operation: A.W.A.R.D.S." spoofs the Spinning Clock Hands version, where the spinning clock hands turns out to be just Numbuh Four playing with his watch.
 * Numbuh Four suffers through this previously during "bring your daughter to work day" in "Operation: O.F.F.I.C.E." He waits and waits and waits... and the hands on his dad's clock move backwards.
 * Those Two Bad Guys: Mr. Wink and Mr. Fibb, parodies of James Bond's Mr. Wynt and Mr. Kidd.
 * Tomato Surprise
 * "Operation: H.O.S.P.I.T.A.L.": the KND guard an operative... who turns out to be a skunk.
 * The movie had the Delightful Children {{spoiler|turn out to be Sector Z, a sector of KND that went missing. Father had tested a machine on them that overloaded and turn them into their current state.}}
 * And of course the real kicker -- {{spoiler|Nigel's father being the original Numbuh Zero, and the brother of K.N.D's sworn nemesis, Father, thus making Father Nigel's uncle}}.
 * Tomboy and Girly Girl: Numbuhs Five and Three.
 * Too Dumb to Live: Numbuh Four loves eating Coco Nut Logs even though he's allergic to coconut.
 * Totally Radical: The "Little Traitor Dudes for Children's Defense" native language.
 * Tranquillizer Dart: Used in "Operation: Z.O.O." by Mrs. Goodwall against Sector V, to put them in a "Kids Zoo".
 * Travel Montage: "Operation: R.A.I.N.B.O.W.S."
 * Traumatic Haircut: More often than not, at least one Kid ends up getting their hair chopped, shaved, pulled, or burned off during a mission.
 * Memorable example is Abigail in "Operation: L.I.C.E.", where her hair is eaten by giant chubby, shrieking mutant lice.
 * It's implied that Numbuh One is permanently bald as a result of being tortured by the DCFDTL.
 * In "Operation: D.A.D.D.Y.", parents giving their own children horrible haircuts is treated like this.
 * Treehouse of Fun: The KND operate from them all over the world and on the moon, and they're usually the largest landmark for miles.
 * Troubled Fetal Position: In "Operation: I.T.", {{spoiler|Father enters this position after being threatened at broccoli-point by Rachel, a.k.a. Numbuh 362, complete with an implied hallucination of his father making him eat broccoli during his childhood. Although given what his father is like, this was probably a truly traumatic experience.}}
 * Troubling Unchildlike Behavior: The afromentioned Creepy Children
 * True Companions: A very central theme of the series, especially applies to Nigel as no matter how busy he is he always puts his friends first.
 * Unnamed Parent: Subverted. To the Kids Next Door, adults are the enemy, and so they don't really care what the adults are named beyond "Mom" or "Dad". All adults are either "Mr. ______" or some variation on the gimmick they use to fight the KND. The biggest villain for the majority of the series is the demonic figure known only as "Father". The one who eventually tops him is the Draculaesque "Grandfather". Three guesses as to the nature of their relationship. In addition, quite a few of the kids' parents are named as the series goes on.
 * Unusually Uninteresting Sight: Sometimes averted, other times played straight. If the Kids Next Door are doing a Humongous Mecha battle in town square for example, you will see civilians running away in terror. However, if the children are jumping into trap doors to escape class, pulling out crazy 2×4 technology in public or participating in other related craziness, expect the people around them to be either indifferent, or to bounce back quickly.
 * For example, in "Operation: E.L.E.C.T.I.O.N.S.", Chad and his friend are in class, wearing their Battle Ready Armor and doing some Evil Gloating complete with dramatic laughter. Neither the teacher nor their classmates seem very interested in the two hamtastic teenagers in lingerie-powered ninja gear. The teacher tells them to wait until after his class to talk about attacking an elementary school, but otherwise doesn't care.
 * Unwilling Suspension: The villains have a fondness for tying up the heroes and dangling them upside-down, usually by their feet.
 * Vetinari Job Security: In "Operation: I.T.", it turns out that Numbuh 362 is the Soopreme Leader because nobody else wants the job. She is genuinely good at it, though.
 * Villainous Crossdresser
 * Chad Dickson in "Operation: S.L.U.M.B.E.R.":

Numbuh 23: Whatever you say, Chaderella. }} {{quote|Numbuh Five: Because the one time Numbuh Five DIDN’T help someone who was kidnapped by The Delightful Children, they did something that she can’t ever forgive!
 * This is actually also a Running Gag: the kids mistake bras for a new kind of weapon in "Operation: S.U.P.P.O.R.T.", which they turn out to be in fact at the end of the episode and in later ones.
 * Villains Out Shopping: A literal example. There is a supermarket specifically for villains only. One episode features the majority of the Rogues Gallery and the heroes fighting over a box of cereal.
 * Villainy Free Villain: Professor XXX-L
 * Wham! Episode: {{spoiler|"Operation: G.I.R.L.F.R.I.E.N.D.", which results in the destruction of Sector V's treehouse and Lizzie breaking up with Nigel}}.
 * Wham! Line: In Operation F.O.U.N.T.A.I.N., Numbuh One cryptically reveals how evil the Delightful Children From Down The Lane can be.

Numbuh Four: What? What’d they do that was so bad?!?

Numbuh One: They made me bald. }}
 * What Do You Mean It's Not Heinous?: Almost all the villains are built on this. Simple things most kids don't like doing such as homework, washing dishes, and eating vegetables are blown to world-destroying proportions.
 * One episode features a hardware-store owner who wants to eliminate two aviators who bought their plane parts from him. Why? Because they kept smudging his counter with chili. Disproportionate Retribution much?
 * This show as a whole is built on this, to an Animal Farm-esque degree. Anything that is kid-oriented is good! Anything that is adult-oriented or that adults make kids do for their own good is vile and evil! Which makes the existance of smutty KND pictures/fanfic somewhat of a violent whiplash of Fridge Logic...
 * This kids = good/adults = bad thing is taken to such a degree that in "Operation: P.O.O.L." it is made to be a bad thing that the adults were doing the things kids do (playing games, getting allowances, etc.) while kids do the things adults do (go to work, taking care of the adults) on a relatively daily basis. How funny that the actions are only awful when they're not being done by their accepted respective age groups.
 * It's normally only shown to be bad when the supervillains take it to extremes; the KND are normally shown having really good relationships with their own parents, even when 86's father is {{spoiler|Mr. Boss}}, and they even state in some episodes that they only fight evil adults. The supervillains' plots are normally something most normal adults in the series would likely have a problem with if they knew (in some cases, this is shown actively).
 * And at the end of "Operation: I.N.T.E.R.V.I.E.W.S.", it's revealed that {{spoiler|adulthood is literally a disease. One that's spreading unchecked across the universe}}.
 * Well-Intentioned Extremist: Played for Laughs with Numbuh 20,000, who tends to go quite a little bit overboard.
 * We Will Have Euthanasia in the Future: A G-rated version: All KND Operatives have to be decommissioned at the age of 13, and their memories of being in the KND will erased. There are teenage operative double agents though, and evil teenagers who escaped decommissioning.
 * Whole-Episode Flashback: "Operation: I.N.T.E.R.V.I.E.W.S."
 * Whole-Plot Reference: "Operation: A.R.C.H.I.V.E." is, surprisingly, basically the Second Renaissance short in The Animatrix with the serial numbers filed off.
 * Who's Laughing Now?: When The Toiletnator sinks an ENTIRE GRAND CANYON'S worth of milk and cereal using his flushing powers.
 * Wild Teen Party: The Delightful Children accidentally start a TV-Y7 version of this trope by trying to kiss up to teenagers. They're forced to ask the Kids Next Door to help them stop the party before Father finds out; the KND are honor-bound to agree.
 * X-Ray Sparks
 * Wake Up, Go to School, Save the World: Not in that particular order.
 * The Wiki Rule: The KND Code Module.
 * The Worf Effect
 * Poor, poor H.I.P.P.I.E.-H.O.P.
 * Numbuh Four would also count, as he would be the first to charge in and is often the first to go down in battle.
 * World Gone Mad: It's a world where adults live to make the younger generations lives a living hell. And people get away with turning stuffed animals and pinkeyeye crust into food. And there's candy pirates who wreck the suburbs pretty damn often, and Father, and Grandfather, and all the villains, and... hell, and some horrible plan about to ruin the lives of children forever and yet their parents always think they're just playing... And then there's "Operation: F.U.T.U.R.E.". My God.
 * World of Ham: You'd be hard-pressed to find a line in this show spoken at normal speed and volume.
 * Xanatos Gambit: There's an episode where Cree's carrying out an Evil Plan to destroy Sector V but is defeated and sent to jail at the KND Moon Base. That was actually her true goal; to gain access to the Moon Base, but wiping out Sector V would have been good too.
 * And then there's "Opearion: P.R.E.S.I.D.E.N.T.".
 * Xanatos Speed Chess: A notable example is when Sector V had to improvise an attack on a "Villains Awards Show" without Numbuh One's help. It involved a lot of disguises, a chunk of sneaking around, and lots of snot. Worked out, until it was revealed that Numbuh One was Kid-napped and set up as an award, causing the plan to backfire. Thankfully, they managed to rescue him in time for the plan to work out. By simply rushing the stage and carting him away. The adults had no clue what was going on.
 * You Are Numbuh Six: Given additional meaning with their, uh, Meaningful Names (see its entry above).
 * The actual Numbuh Six is a skunk. No hidden meaning there, he's just a skunk. But Numbuh Six was introduced before it was revealed that Numbuh's One through Five were just a sector of a much larger KND operation. Also, Bradley the skunk isn't an official Numbuh. Numbuh One granted him honorary status after the events of "Operation C.A.M.P." They treat the honorary designation as official, however, even coming to Bradley's aid in "Operation: H.O.S.P.I.T.A.L."
 * You Know What You Did: "Operation: D.O.G.F.I.G.H.T."
 * You Meddling Kids: "Operation: C.A.M.P."; a angry camp counselor yells at a skunk, the one later used in the Tomato Surprise, after the KND freed a bunch of Brainwashed campers.
 * You Monster!: Numbuh 86 to Father, in "Operation: C.A.K.E.D.-F.I.V.E.", after the destruction of the KND ice cream storage.
 * Zombie Apocalypse
 * Or rather a Senior Citizombie Apocalypse in The Movie.
 * An earlier episode also dealt with nerd zombies. {{spoiler|In that case, though, it was due to a collectible card getting stolen. Once it was returned, they changed back.}}

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