[[quoteright:320:https://static.tvtropes.org/pmwiki/pub/images/3_ninjas.png]]
[[caption-width-right:320:[[{{Tagline}} Comin' at you!]]]]

->'''Rocky:''' We should run.\\
'''Tum Tum:''' We should hide.\\
'''Colt:''' We should kick their butts!
-->--''3 Ninjas''

The ''3 Ninjas'' series is about three young brothers who are trained to be ninja-like by their grandfather. The original ''3 Ninjas'' is an 1992 martial arts comedy, directed by Jon Turteltaub. It features Mori Tanaka (Creator/VictorWong), a Japanese grandfather who teaches his American grandsons martial arts. Three of the four films were produced by Shin Sang-ok (as Simon S. Sheen), most known for directing ''Film/{{Pulgasari}}''. [[HeAlsoDid Yes, it's that guy!]]

Said grandsons are promptly introduced and receive proper codenames. Samuel Douglas Jr. (Creator/MichaelTreanor), is physically strong, tough, and remains strong and cool under pressure. His codename is "Rocky". Jeffrey Douglas (Max Elliott Slade) is fast and free, "with the spirit of a young wild horse", receiving the codename of "Colt". Michael Douglas (Chad Power) is a BigEater. His codename is "Tum Tum". The trio must help their grandfather against [[APupilOfMineUntilHeTurnedToEvil a rogue student of his, who has turned career criminal]]: the dangerous Hugo Snyder (Rand Kingsley).

The film involves the boys facing Snyder and his agents, along with having a rivalry with some school bullies, and Rocky's relationship with his first {{love interest|s}} Emily (Kate Sargeant).

It was a modest box office hit: earning $29,000,301 in the United States market. The film was lucrative enough to receive sequels. Two were produced almost immediately. However, they were curiously released in reverse order. What was to be the intended third film was released second, the second film was released third, causing some internal logic problems.

The second film to be released was ''3 Ninjas Kick Back'' (1994). Grandpa Mori plans to visit Japan to return a dagger he has held for 50 years, apparently to serve as a prize in a martial arts tournament. He takes his grandsons with him for what he hopes to be a bonding experience. The boys have grown up somewhat and their different interests have made them drift apart. Rocky is having trouble concentrating on anything other than cute girls, his latest crush being Lisa Di Marino (Creator/MaitalSabban). Colt has developed a HairTriggerTemper and can be counted to pick up fights left and right. Tum-Tum has become even more obsessed with food. They barely have anything in common anymore. When they discover someone has sent thugs to retrieve the knife and that their grandfather has had a very suspicious accident, they travel to Japan on their own to investigate. There they team-up with a female martial artist, Miyo (Creator/CarolineJunkoKing). She might be young but is even better-trained than them. She even agrees to give them some lessons, in exchange for them tutoring her in baseball. Naturally, amorous Rocky has forgotten all about Lisa, shifting his attention to Miyo. The film was not as financially successful as its predecessor, and critics dismissed the film. However, it earned $11,798,854 in the United States market, the 104th most successful film of its year. It did very well in the VHS market, particularly among younger viewers.

The third film is ''3 Ninjas Knuckle Up'' (1995). This time Colt gets a love interest in Jo (Crystle Lightning), a Native American girl whose village comes under threat of becoming a toxic waste dump, due to a CorruptCorporateExecutive. Continuing the decline of the series' commercial value, the third film earned just $413,479 at the box office.

A fourth film was released, featuring a new cast of actors in the roles of the Douglas Brothers. ''3 Ninjas: High Noon at Mega Mountain'' (1998). The film starts with the trio failing at a training exercise. Rocky and Colt grew disillusioned with the regimen and thinking they are too old for it. Rocky would rather spend time with his current girlfriend Jennifer (Creator/LindsayFelton) than spending time with grandpa. Soon, the trio team-up with their new friend, computer nerd Amanda Morgan-Greene (Creator/ChelseaEarlywine) in order to diffuse a difficult situation. Retiring ActionHero Dave Dragon (Wrestling/HulkHogan) becomes the hostage of a group of kidnappers, led by mastermind Medusa (Creator/LoniAnderson), along with any other people placed in danger due to her plans. By the end of the film the victorious trio are back to training, with a new appreciation for it, with Amanda joining them as the fourth ninja of the group. The fourth film was a massive flop, earning only $375,805 at the box office.

----
!!This film provides examples of:

* AdultsAreUseless:
** Averted in the first film. The kids would most likely have been shot if their dad and his police buddies hadn't shown up.
** In ''Knuckle Up''. Jo's dad starts out as a DistressedDude, but he's the one who discovered the evidence of Jack Harding's illegal waste dumping in the first place. He also withstands four days of torture, and he and a friend manage to fight off and escape several mercenaries who attack them in the final act.
** Also averted several times in the final movie.
*** Martial arts star Dave Dragon has several scenes of fighting back against the mercenaries holding the park hostage (and ultimately is the one to get rid of the bomb when the kids aren't strong enough to).
*** The performers in a western stunt show lasso several henchmen (albeit after being beaten up by them when they try to physically stop the thugs) after the first martial arts fight of the film.
*** One of the ride attendants is shown doing a responsible job making sure that riders take the proper safety precautions.
** Additionally, the kids' grandfather is a CoolOldGuy who is nearly as competent and important as they are in the first three movies.
* AnAesop: One for each movie.
** In ''3 Ninjas'', it mostly applies to Colt, though Rocky and Tum Tum also have their moments. Don't lose faith in people simply because they are (or used to be) associated with a criminal. Sometimes, they may not even be aware that the other person ''is'' engaged in criminal activities.
** In ''Knuckle Up'', the three ninjas come to Jo's defense at the beginning, but cause property damage and were primarily doing it "to be heroes", which as their grandfather points out is not helping others, it is helping ''themselves''. Their grandfather then asks them to listen to the sound of the flowers blooming. This seems like nonsensical advice until near the end of the film, when they finally get it -- of course the flowers don't make any sound when blooming, because flowers concentrate more on ''being'' pretty than on ''acting'' pretty. The same should be true for their heroism; if they really want to help others, they should do it without making a big production out of it to get attention.
** In ''Kick Back'', the Aesop is about the value of self-control and restraint. At the beginning of the film, the boys inadvertantly cause a baseball game to be stalled because they lack these qualities: Tum Tum keeps his eye on food instead of on the ball, Rocky messes up a pitch because he's distracted by the pretty Lisa Di Marino, and Colt responds to the provocations of the opposing team by starting a fight that then escalates into a brawl. After their adventure in Japan, the boys return calmer, and this time they help win the baseball game.
** ''Mega Mountain'' has two.
*** When a ninja's head swells up with pride, they lose focus and cannot see despite having eyes, so humility is an important virtue (as well as the ability to sense your environment using your ears rather than your eyes).
*** Growing up may mean seeing your idols in a more negative light (Rocky and Colt think they've "outgrown" their grandpa's ninja training and need to move on to "grown-up" things, while Tum Tum (plus a young boy at the park) sees that Dave Dragon isn't as perfect a fighter as he is on TV), but they may still have admirable qualities for you to learn from.
* AMFMCharacterization: Hammer wears a Music/{{Metallica}} shirt and puts up stickers of the different Metallica albums in the phone booth.
* AnachronicOrder: ''Knuckle Up'' was supposed to be released before ''Kick Back'' (as one clue, ''Knuckle Up'' features the three ninjas' actors from the original film, while ''Kick Back'' has replaced Rocky and Tum Tum's actors with only Colt's actor reprising his original role), but due to legal issues, ''Knuckle Up'' was released a year after ''Kick Back''. So ''Knuckle Up'' was supposed to be the second movie, and ''Kick Back'' was supposed to be the third.
* AttackItsWeakPoint: "The eyes, boys! Light up the eyes!"[[note]]They had practiced with a training dummy whose eyes light up when you hit vulnerable spots. This does include kicking them [[GroinAttack in the nuts]].[[/note]]
* ArtisticLicenseMartialArts: Where to begin...Rocky, Colt and Tum Tum are able to beat up several bigger and stronger adult opponents in rapid succession. In ''Knuckle Up'', they even [[CurbStompBattle curbstomp an entire biker gang]]! Even a well trained real-life kid ninja would have trouble with multiple attackers bigger or more numerous than they are. Aristic license though is probably done for both RuleOfCool and RuleOfFunny. This varies considerably between entries; in the first movie the boys are forced to fight evasively against their completely unskilled attempted kidnappers, then take on the guards one by one through stealth and trickery, finally taking on TheDragon three-on-one and only getting their attacks to register ''at all'' through the use of low blows and pressure point strikes.
* BadassFamily: The boys are ninjas-in-training, Grandpa's an OldMaster, and their dad is an FBI agent.
* BadassAdorable: Miyo is pretty enough for Rocky to fall in love with her, and she can kick butt, too.
* BadassTeacher: Grandpa doesn't just train the three brothers, he has his own fight scenes.
%%%* BadBoss: All of the Big Bads, though Snyder is by far the worst.
* BaitAndSwitch:
** The surfer dudes in the first movie are huddled around a surfing magazine with a bikini girl on the cover, exclaiming how they would like to spend some quality time on a lonely beach with the babe they are looking at. Cut to the magazine photo; they are actually just looking at a picture of a new surfboard.
** Fester and co. force the boys' nanny into a closet by shoving an entire pizza into her face.
-->'''Hammer:''' [appalled] Uncool, bro.\\
(reaches inside and grabs a slice)\\
'''Hammer:''' [beaming] Much better.\\
'''Fester:''' [[SarcasmMode Dude, sensitive]]!
* BigBad: Snyder in the first movie, Koga in ''Kick Back'', Harding in ''Knuckle Up'', and Medusa in ''High Noon at Mega Mountain''.
* BigEater: Guess how Tum Tum got his nickname...
* BigNo:
** Rocky gets one in the final battle between Snyder and Grandpa, in slow motion no less.
** Dave Dragon has one in ''High Noon at Mega Mountain'' when Medusa locks Amanda out of the system while trying to regain control of the park.
* BigShutUp: When the boys overreact to a practice dummy.
-->'''Grandpa:''' Quiet, boys!\\
'''Boys:''' Yes, sir.
* BilingualBonus: In ''Kick Back'', the ninja brothers are in Japan so there are naturally people speaking Japanese there.
* BirthdayEpisode: ''Mega Mountain'' takes place during Tum Tum's birthday, and he even gets to blow out candles on a birthday cake at the very end of the film.
* BringMyBrownPants: Naturally, the result of the LaxativePrank in the first film. The people in question actually make it to the bathroom.
* BrokenRecord: ''Rocky loves Emily! Rocky loves Emily! Rocky loves Emily!''
** Other examples pop up in later films, with the brothers repeating "Colt's gonna kiss Jo!" at the end of the second, "Rocky loves Miyo!" in the third, and "Rocky loves Jennifer!" in the fourth.
* BrutalHonesty: When Medusa's thugs take Dave and a bunch of park visitors hostage, a young boy asks Dave if he is a real hero or merely a stage actor. Dave, not wanting to disappoint the boy, can only say that his Closed Fists are not very effective against firearms.
* BumblingHenchmanDuo: In ''Knuckle Up'', the cowboy-hat wearing head henchmen always has the same two goons backing him up. Three Stooges-like hijinks occur.
* CallBack: In ''Kick Back'', when a heavyset martial artist and a sumo wrestler confront the three ninjas on a rooftop, the three ninjas are able to prevail by "lighting up the eyes" (that is, hitting them in their weak points), which recalls how they defeated Rushmore in the first movie.
* CarChase: There are two of them in ''Knuckle Up''; Jo's father evading some of Harding's goons while trying to get to the hearing, and the boys chasing after some more of Harding's goons to rescue Jo.
* CatchPhrase:
** "We should run!" "We should hide!" "We should kick their butts!"
** "Let's murdalize 'em!" which itself gets murdalized in the third film when Tum-Tum's new actor pronounces it too-properly as "Let's murderlize 'em."
* CardCarryingVillain: Snyder in the first movie.
--> "God, I love being a bad guy."
* ChainedToARailway: A variant of this trope is done in ''High Noon on Mega Mountain'' with Jennifer being tied to the tracks of a roller coaster.
* ChickMagnet: Rocky, attracting Emily in the first movie, Miyo in ''Kick Back'', and Jennifer in ''Mega Mountain''. Jo from ''Knuckle Up'' is the only exception, as she's attracted to Colt instead.
* CombatParkour: The three main characters use this in their fights and, being ninjas, are masters at using their environment to their advantage in a parkour style.
* ConservationOfNinjutsu: Nameless crowd mooks fare the worst against the ninja brothers. Even the three surfer-dud kidnappers from the first movie last longer. However, the first movie features a zigzag, [[spoiler: when the ninja brothers are severely outnumbered near the end, they give up. Then their OldMaster grandpa shows up and they start fighting again but the crowd of bad guys are only truly defeated when their dad shows up with cops.]]
%%%* CorruptCorporateExecutive: Harding in ''Knuckle Up''.
* CouldHaveAvoidedThisPlot: In ''Kick Back'', the boys initially choose to go to their baseball game instead of traveling to Japan with their Grandpa. It is not until the important stuff has been done that they realize [[spoiler: that Japan is a day ahead of America, meaning that they can do both.]]
* CutLexLuthorACheck: Koga in ''Kick Back'' has been obsessed with finding the legendary "cave of gold" for fifty years, but in the present day, he appears to already be an incredibly wealthy businessman with his own army of ninjas; one wonders how much richer the gold could really have made him. To be fair, he [[HeelRealization seems to realize]] how unreasonable his greed was at the end.
* DamselInDistress: Emily in the first film is grabbed by the surfer-dude kidnappers. Jo gets in trouble in ''Knuckle Up'' (though Jo ''tries'' to take down the bad guys and is simply overpowered), and Jennifer in ''Mega Mountain'' is also imperiled. Thankfully, [[ActionGirl Miyo]] averts this, because she is a ninja/martial artist like the brothers.
* DancePartyEnding: Subverted. About halfway through ''Knuckle Up'', the heroes have rescued the Love Interest's dad and break out in a flawlessly choreographed ninja/break-dance performance, but are interrupted by the villains arriving to begin the second act.
* DarkerAndEdgier: ''Knuckle Up''. The film was given a PG-13 rating and includes scenes such as Rocky going up against a knife-wielding fighter.
* DemotedToExtra: Grandpa Mori plays a much more active role in the first two films than the latter two.
* DescriptionCut:
--> '''Fester''': We should save some of this (pizza) for the kids we're napping.
--> '''Marcus''': ''[beat, nods]'' Dude!
--> '''Hammer''': They're probably pretty nice kids.
--> (Cut to-)
--> '''Colt''': Where are all the weapons?! The slingshots, the knife-throwers?!
**
-->'''Colt''': Grandpa isn't coming! He sold us out!
-->(Cut to-) ''Grandpa knocking out a mook as he climbs onto the ship to rescue the boys''.
%%%* DieHardOnAnX: In ''High Noon at Mega Mountain''.
* DidntThinkThisThrough: In the first movie, the grandfather is nearly cornered by a group of ninja who begin to dramatically unsheathe their back holstered swords... but can't get them out because the hallway they are in is too small for such a sheathe to work.
* DoesntLikeGuns: Rocky can tell who the bad guys are when he sees them carrying guns. [[NoTrueScotsman He also doesn't consider Snyder's ninjas to be true ninjas because they carry guns also]].
* DotingGrandparent: Mori Tanaka clearly adores his grandkids and delights in training them.
* TheDragon:
** Rushmore in the first movie is Synder's chief enforcer and a major challenge to the ninja brothers.
%%%** Lothar in ''High Noon at Mega Mountain''.
* DrivesLikeCrazy: In ''Knuckle Up'', Rocky commandeers a car in order to chase after mercenaries, but since Rocky is a young boy, he can't drive very well. In ''Kick Back'', in order to get to the airport, the three ninjas hire a Super Shuttle, and the driver drives so fast that the three ninjas are screaming the whole way (but in this case driving like crazy actually ''does'' help, since the driver is able to reach the airport extremely quickly).
* EvilPlan: In order: {{Revenge}}, finding a chamber of gold, shady business, hijacking a theme park for ransom.
* ExcuseMeWhileIMultitask: In ''Kick Back'', the boys fight off a pack of ninjas while taking a phone call from their mother. They actually toss the phone to each other during the fight so she can talk to each of them, and explain away the noise as an action movie on TV.
%%%* TheFamilyForTheWholeFamily

* FamilialFoe: The BigBad of the first movie is a sworn enemy of both the eponymous brothers’ maternal grandfather (his former mentor, who hates him for turning evil) and father (a federal agent investigating him for arms smuggling). He sets out to kidnap the boys to get leverage against their father and grandfather, and ends up pretty frustrated with the boys due to how competent they are at fighting his men.
* {{Foreshadowing}}: When the kids return home and go to sleep in the first movie, Tum Tum chokes on a jellybean. Mori [[spoiler: uses jellybeans to choke Snyder and gain the upper hand in their fight.]]
* FunnyForeigner: Miyo seems strange to the brothers but, in a inversion, ''they'' are the foreigners because much of the plot takes place in Japan.
* GirlOfTheWeek: Rocky has at least one different love interest in every movie except ''Knuckle Up'', where Colt is the one to fall for the female lead.
** In the original movie, literal GirlNextDoor Emily and Rocky have some PuppyLove.
** In ''Kick Back'', Rocky wants to impress a girl named Lisa during the baseball game. However, later in the movie, he and Miyo have a MeetCute moment when they both have to take out reading glasses, and they quickly become romantically attached.
** In ''High Noon at Mega Mountain'', Rocky is dating a girl named Jennifer.
* GreaterScopeVillain: Colonel Farouk in the first film. He never appears in the movie and is mentioned several times by Snyder. But Snyder answers to him.
* {{Greed}}: This is the primary motivator of the BigBad in all the films.
%%%** In ''3 Ninjas'',
** In ''Knuckle Up'', Jack Harding is trying to cover up evidence that his business is polluting the land, which if revealed would get his business shut down.
** In ''Kick Back'', Koga is trying to find a hidden chamber of gold, and as a youth was willing to try to steal a dagger from Mori because that dagger would lead him to the gold.
** In ''Mega Mountain'', Medusa is trying to take over an amusement park just for ransom money.
* GroinAttack: Used a couple of times in the first film - one for Fester and one for Rushmore. The boys also do this on a training dummy. The groin is in fact pointed out as one of the key weakpoints of the body to attack by Mori.
** Tum Tum hits the dummy in the groin a lot.
* GirlOfTheWeek: Each of the movies features a different female character in the role of a potential LoveInterest, and as noted above almost all of them are attracted to Rocky.
* HollywoodGenetics: While it is clear they are trying to justify [[MightyWhitey white-washing]] by casting Caucasian actors as the Douglas brothers, who have an Asian grandfather, it is possible for the children of someone of Asian descent to not look Asian themselves. It's possible that their grandfather married a white woman, making the boys' mother half-Asian ( [[FakeMixedRace who is still played by a white actress]]), and considering she married a white man, the boys are only a quarter Asian, presumably why they look white instead of Asian. Unless of course if their mother was fully white and HappilyAdopted by their grandfather, the movie implies that he's their grandfather by blood.
* HomeAloneAntics: Both the original film and ''Kick Back'' feature traps set within a house that trip up the intruders.
* HopeSpot: In ''High Noon at Mega Mountain'', Amanda uses her laptop and tries to regain control of the park by overriding [[BigBad Medusa's]] controls, but Medusa quickly regains her control of the park and locks Amanda out of the system.
* HostageForMacGuffin: In ''Knuckle Up'', Jack Harding has mercenaries kidnap Jo as leverage so her father will give Harding an incriminating disk that would otherwise prove Harding's landfill has been polluting the land (which would result in Harding's landfill being shut down if this were revealed).
* TheHyena: Ishikawa, TheDragon in ''Kick Back'', is prone to mean-spirited, braying laughs.
* ImprovisedWeapon: "Everything around us can be our friend. Be friendly to your environment. That is the ninja way." About a minute later, Rocky takes out a mook with a ''telephone''.
%%%* InjunCountry: In ''Knuckle Up''.
* InsistentTerminology:
** The brothers argue back and forth during the original film's opening narration about the use of "My brothers and me" vs "My brothers and ''I''."
** And don't forget that Fester and his goons aren't robbers, they're ''kidnappers''.
* InsultToRocks: Tum-Tum insults TheDragon for stealing his donut in ''Kick Back''.
--> '''Tum-Tum:''' You ape! Did I say ape? Forget it. It's not fair to other apes.
* {{Kevlard}}: Rushmore, the GiantMook in the first movie. Until the heroes figure out where his weak points are, their blows simply do not register.
* KidHero: The three brothers are varying ages but all of them are teenagers to kids when they fight bad guys.
%%%* KnightKnaveAndSquire: Rocky, Colt and Tum Tum.
* LampshadedDoubleEntendre: In ''Kick Back'', Miyo is skilled in ninjitsu but wants to learn how to be better at baseball. Her speech pattern has her jumble the words "bat" and "butt". She wants to [[DoubleEntendre "Swing my butt!"]] and "Kick bat".
* LaxativePrank: The boys use this as a way to defend themselves against the bumbling [[InsistentTerminology kidnappers]] in the first film. It results in their getting stuck on the toilet.
* LetsGetDangerous: In all films except ''Mega Mountain'', the grandpa gets a moment where he cuts loose after being kindly and calm for most of the film.
* LittleMissBadass: Miyo defeats multiple opponents with relative ease.
* MatchCut: The brothers' parents talking while driving back home. The mother tells her husband that the boys love their grandpa and the ninja teachings. The father worries that "someone could get hurt". Then we cut to Emily entering inside the house where the three {{surfer dude}}s are about to ambush her.
* McNinja:
** Admittedly, while the Three Ninjas are in fact very competent in terms of their pure martial arts skills, their grandfather is not teaching them real-life ninja philosophy. To name just one example, real-life ninjas did not live by codes of honor that would involve body, mind, spirit, and heart or anything that noble. {{Justified|Trope}}, however, because their grandfather does not ''just'' want to teach them how to be ninjas, he wants them to grow up moral and good. It makes perfect sense that he'd be willing to take a few liberties with what sort of people ninja are supposed to be.
** The Mooks are a much clearer example; they're pretty clearly generic thugs with negligible skill in martial arts wearing costumes to be thematic. The boys even call them on this when they see them openly patrolling with rifles.
* MenOfSherwood: Many minor reservation residents play minor roles in a couple of fight scenes (the pow-wow and the road ambush) and help the boys deal with ZergRush numbers of {{Mook}}s.
* {{Mooks}}: Both the ninjas and the incompetent kidnappers.
* NewOldWest: ''Knuckle Up'' features the brothers going up against a greedy, influential Caucasian businessman with lots of {{Cowboy}} {{Mook}}s trying to avoid justice for his crimes against the local Native Americans. The setting is more rural than in the other films, and the climatic fight takes place in a western GhostTown.
%%%* TheNineties
* NoGoodDeedGoesUnpunished: In ''Knuckle Up'', the three ninjas come to Jo's defense in a pizza place against some goons who were treating her roughly, but because they damage the property in the process, they end up punished by their grandfather. He sends them to help clean up the place and take out the garbage, doing work to pay off the damage. This is a more justified example than most uses of this trope, however, as the three ninjas confessed to their grandfather that their primary motivation for helping Jo was "to be heroes", and as their grandfather points out, heroes are more concerned with helping others than they are with making themselves look cool.
* NotInTheFace
-->'''Hammer:''' Ooh! Watch my nose, dude! It's bad news already!\\
''[A CD hits his nose. Marcus laughs, but gets hit too]''\\\
'''Hammer:''' Not the stomach! Not the stomach!\\
''[Rocky and Colt elbow him in the nose]''\\
'''Hammer:''' Thank you. ''[passes out]''
* NotSoHarmlessVillain: Medusa from ''Mega Mountain''. She doesn't seem too threatening an antagonist at first, as her plan only involves taking over the Mega Mountain amusement park to extort ransom money from its owner, Harry Jacobson, but then Medusa reveals that if Jacobson doesn't cough up the money by 3:00, Medusa will sabotage the rides and ''kill people!'' And so many would die that Medusa jokes the park would be renamed ''Murder'' Mountain. Later, she attempts to run over Rocky and Jennifer by remote-controlling a roller coaster, and near the end, Medusa first threatens to make Amanda work as her slave, and then attempts to ''kill Amanda with a bomb''. Given that ''Mega Mountain'' is the campiest film in the franchise, Medusa turns out to be a much nastier villain than she first seems to be.
* ObviousStuntDouble:
** In some of Grandpa's fight scenes, it's glaringly obvious that a stunt double is used. The gymnast stunt man is clearly taller and many pounds lighter than the heavyset Victor Wong and the fight double has '''far''' more hair. Bonus points for the apparent pillow the double is wearing under his costume to simulate Grandpa's heavier weight.
** In ''Knuckle Up'', every fight scene involving Rocky and Colt show them to be very obviously not played by their actual actors. With enough use of freeze-frame, it seems like both of them are played by the same full-grown Asian man.
* OldMaster: Grandpa is an old ninja with much experience and skill, which he is passing on to his grandkids.
* {{Only Known by Their Nickname}}s: Throughout the franchise the brothers are always referred to by their ninja names - with a few exceptions. Notably, their father refused to ever call them by their nicknames until the end of the first film.
* OutOfCharacterAlert: In ''Mega Mountain'', the three ninjas' mother fixes Tum Tum a huge sandwich with lots of ingredients--and Tum Tum actually refuses food for once, saying he's not hungry. This signals to the audience that the cancellation of Dave Dragon's show and his brothers' growing ambivalence to ninja training is ''really'' weighing on Tum Tum's mind.
* OutrunTheFireball: Rocky and Colt do this in ''Knuckle Up'' when the villains pour flammable gas into the manhole they were escaping from.
* OutsideRide: In ''Knuckle Up'', the boys escape one confrontation with the villains by riding on the back of an ice cream truck. Naturally, [[SweetTooth Tum-Tum]] has a souvenir.
* ParentsInDistress: Jo's father is in trouble at the beginning of ''Knuckle Up''. Unusually for this trope, this is solved halfway through the movie, as the three ninjas and Jo are able to rescue Jo's father very quickly. Unfortunately, Jack Harding then resorts to having Jo herself kidnapped instead.
* ThePiratesWhoDontDoAnything: The three goons in the first film insistently refer to themselves as kidnappers, not robbers, but they never get the chance to actually kidnap the boys.
-->'''Colt:''' [[SarcasmMode Oh no! Robbers!]]\\
'''Hammer:''' Robbers? I thought we were kidnappers.\\
'''Fester:''' We are!
* PostGameRetaliation: In ''3 Ninjas Kick Back'', the defeated baseball team goes for "extra innings" - that is, attack the victorious players and their friend Miyo in the parking lot. One of the boys decides to fight Miyo, but [[CurbStompBattle it does not end well for him]].
* PunchPunchPunchUhOh: The kids' "beating up grown mercenaries" mojo isn't so effective against [[TheDragon Rushmore]]. At the film's climax, they get around it with Mori's help in the "Light up the eyes!" scene.
* PunnyName: The kids' dad's FBI partner, Jerry, is listed in the credits as "FBI Agent Kurl". So he's Jerry Kurl.
* QuirkyMinibossSquad: Each movie has a set.
** The surfer trio from the first film.
** The hick trio in ''Knuckle Up''.
** The BigBad's nephew and his two friends in ''Kick Back''.
** The bumbling trio of funlovers in ''Mega Mountain''.
* RecordedSplicedConversation: One scene in ''Kick Back'' has the kids use a recording of their grandfather calling them to buy tickets to Japan, cutting the call after their grandfather starts insulting the airline agent (he was actually talking about the BattleaxeNurse in the room with him). Unlike most examples of this trope, this one doesn't go quite perfectly and Colt accidentally lands the rewind in the wrong spot a couple of times, making for some funny mistakes that lead to a very upset airline phone attendant.
* RecruitTheMuggles: In ''Knuckle Up'', while the main focus of the reservation fight scene is on the main characters, there are a few brief shots of the previously cowed tribal members fighting back as well.
* SayYourPrayers: Tum Tum does this during the CarChase in ''Knuckle Up''. He's still doing it even after the car has stopped.
* SequelGoesForeign: In ''Kick Back'', the boys go to Japan to deliver a MacGuffin to Grandpa Mori.
* SpotTheImposter: In ''Kick Back'', Koga disguises himself as the grandmaster so the three ninjas will hand him the dagger he wants. The ninjas are able to figure out he's a fake because he's suddenly speaking English, he's wearing shoes when the real grandmaster goes barefoot, he's suddenly asking for the dagger even though Mori (who is traditionally supposed to give the dagger) hasn't arrived yet, and he's taller than the grandmaster.
* StandYourGround: In ''Knuckle Up'', when several truckloads of thugs show up at the Native American reservation to try and steal back evidence that they've been dumping toxic waste. The local leader, Jo's dad, yells for the people to stand there and face their assailants down.
--> '''Charlie:''' Don't run! Don't run!
%%* ThugDojo: The main antagonists of the first movie.
* TotallyRadical: "Cake" which could be "Piece of Cake". In fact, in ''Knuckle Up'', the DVD subtitles actually write it as "Piece of cake" at one point.
* TrainingMontage: Miyo in ''Kick Back'' is an even better ninja than the three ninjas are, but she is comically inept at baseball. So she and the three ninjas strike up an agreement: the three ninjas will train her to get better at baseball, and in exchange she'll teach them how to improve their ninja skills. What follows is an alternating montage of Miyo and the three ninjas training each other.
* UndercoverCopReveal: In the first movie, Snyder is introduced selling weapons to an accented man in Arabian headgear. His customer smiles and announces that on behalf of the people of his country, he'd like to say [[BaitAndSwitchComment that Snyder is under arrest]]. As he says that, his accent disappears, and he pulls out an FBI badge. Snyder barely escapes.
* UnderestimatingBadassery: A strong contributing factor to the three ninjas winning most of their fights is that they're young boys so their opponents approach them believing they'll be easy pickings, only to discover that the three ninjas are ''ninjas'' for a ''reason''.
* UnwantedGlassesPlot: A minor example occurs in ''Kick Back''; Rocky is reluctant to reveal in front of others that he needs glasses to read, but this actually allows him to bond further with Miyo when she reveals she also needs glasses to read.
* VillainsOutShopping: In ''High Noon at Mega Mountain'', Medusa's nephews and accomplices get in line for one of the amusement park's rides rather than patrol the park like they're supposed to.
* WeaksauceWeakness: Subverted. A mouthful of jellybeans would normally be a pretty stupid secret weapon, but Grandpa stuffs them down the BigBad's throat with the intention of choking him long enough for Grandpa to gain the upper hand.
* WeWillMeetAgain: In ''Knuckle Up'', a furious Harding vows "This isn't over yet!" when the judge orders his landfill permanently shut down. Unfortunately for him, it's an empty threat at that point and he's immediately contradicted with "It's very over".
* WhatHappenedToTheMouse:
** It was never revealed what happened to Fester, Hammer and Marcus; the three criminal surfer punks sent to kidnap Rocky, Colt and Tum Tum. Before the police arrived to the Douglas' house, Brown and Rushmore showed up to the house to kidnap the three kids. Then, when the police arrived to the Douglas' house, the three criminal surfer punks were not seen or mentioned.
** In ''Kick Back'', Ishikawa is last seen after being knocked unconscious in a tunnel system which later collapses.
** In ''Knuckle Up'', several of the bikers who kidnap Jo and then ambush the brothers at the ghost town aren't seen during the following fight.
** In the climax of ''High Noon at Mega Mountain'', the heroes blow up the ship Medusa and several of her henchmen are on. Medusa is arrested after she swims ashore, but there's no sign of the four bumbling henchmen who jumped overboard with her, making it unclear whether they escape, drown offscreen, or are arrested floundering near the wreck. Additionally, there are at least two RedShirt {{Mook}}s on the ship who ''aren't'' seen jumping off, and it's unclear if they die in the explosion or manage to abandon ship offscreen.
* WhatTheHellHero: In ''Knuckle Up'', the three ninjas come to Jo's defense after she's treated roughly by Harding's goons, and the three ninjas win the fight...but in the process, they cause a lot of property damage to the pizza place they were in, causing their grandfather to lecture them that if they were primarily defending Jo "to be heroes". That is not helping others, that is helping ''themselves''.
* WithGreatPowerComesGreatResponsibility: A non-superpower variant, and a major plot point in ''Knuckle Up''. Mori berates the boys for not only using their ninja training to show off, but also for causing property damage to a pizza parlour, even if it ''was'' to help a girl who was being harassed.
--> '''Mori:''' Helping others to become a hero isn't ''really'' helping them, but helping ''yourself''. It's a lie!
* WorldOfActionGirls:
** Miyo practices martial arts just like the three brothers.
** In the first movie, Emily isn't a trained fighter like Miyo, but she does kick the man holding her hostage in the shin and then punch him in the face, then casually says, "No sweat."
** In ''Knuckle Up'', Jo spends a lot of time as a DamselInDistress. Still, she injures some goons with blunted arrows while helping rescue her dad and knocks out a biker during the fight at the ghost town.
* WouldRatherSuffer: In ''Mega Mountain'', shortly after capturing Dave Dragon, Medusa offers to have mercy on him and make him her "boy toy". Dave Dragon replies that he would rather be eaten alive by wolves.
%%* YesMan: Tum Tum to Colt.
* YouHaveFailedMe: In ''Kick Back'', when Koga's nephew and his two friends bring back a tape of a conversation but not the dagger Koga is looking for, Koga tells his nephew and friends that they have failed him, and motions for a henchman to punish them. But then the usual implications of this trope are subverted; instead of being killed for their failure, Koga's nephew and his two friends are just tossed into a pool to get wet.
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