Alpha Bitch: Regina and, later, Cady. The whole movie is arguably a Deconstructive Parody of this trope, demonstrating how a girl can be so simultaneously loved, feared, and hated by the rest of the student body.
Ambiguously Gay: Regina claims Janice Ian is a lesbian, though she's actually Lebanese. Her outfits reinforce the stereotype, but by the end of the film it's obviously not true.
Backhanded Apology: When choosing a fault to apologize for before falling backwards and letting others catch you, it is not a good idea to apologize for being so popular it makes everyone else jealous.
Janis also does this with Regina when she "apologizes" for helping Cady in sabotaging her and says she did it because "I guess I've got a BIG, LESBIANCRUSH ON YOU!"
Badass Teacher: Principal Duvall. Doesn't do anything typically badass during the film, but sometimes sheer presence is enough: looking at the man, especially when he's giving a stern lecture whilst wielding a baseball bat, just tell me you wouldn't a) hang on to his every word or b) not want to take him on in a fight.
Based on an Advice Book: Queen Bees & Wannabes by Rosalind Wiseman, written as a guide for parents with teenage daughters to help them understand the social structures and viciousness of high school life.
Bilingual Bonus: Trang Pak and Sun Jin Dinh's dialogue becomes a lot funnier if you speak Vietnamese. Also, at the end of the movie, when Gretchen is brown-nosing to the Cool Asians in Oriental-sounding gibberish, one of them says (in confused and unsubtitled Vietnamese), "What?"
Bowdlerization: Tina Fey's original script was rated R, and was filled with sexual innuendo, drug humor and "wall-to-wall titties" (Fey's words) in the vein of such teen sex comedies as Porky's and American Pie. Several scenes that were in the movie were raunchier in their original form — the "made out with a hot dog" line was originally supposed to say "masturbated," (and in fact, if you read the girl's lips when she says, "Made out with a hot dog? That was one time!" she obviously says masturbated, it's just dubbed-over.) Regina and Karen's Halloween outfits (already stripperiffic in the final film) were basically bras and panties, and the scene where Gretchen and Jason are caught making out in the bathroom originally had Gretchen about to give Jason a blowjob. There was also a subplot involving an ecstasy-popping raver kid named Barry that was dropped from the finished product.
The script was toned down after Lindsay Lohan was cast in the lead role, due to the fact that she was then considered a family-friendly teen actress (which became Hilarious in Hindsight several years later after her scrapes with the law). Even then, the film had to be edited further to receive a PG-13, a lot of crap got past the radar, and an astute observer can spot some lines that were dubbed over in order to tone the film down.
The film gets edited further when it is shown on ABC Family.
One could argue this is for the better, as it makes Mean Girls more accesible to the teen demographic that can relate to the characters, and also makes it stand out from the pack of movies in the genre.
California Doubling: As Roger Ebertput it, "She enrolls in Evanston Township High School — which, like all American high schools in the movies, is physically located in Toronto"
Can't Believe I Said That: Invoked by Gretchen a couple times when insulting Regina. It's pretense, of course.
Chekhov's Gun: Chekhov's big yellow school bus, rather.
Chekhov's Lecture: "Everybody in the English speaking world knows that song."
Cool Loser: Janis Ian. She used to be popular, but during middle school, Regina spread rumors claiming that she was a lesbian.
Cloudcuckoolander: Karen ("My breasts can always tell when it's going to rain. Well, they can always tell when it's raining." and standing in the rain, feeling her breasts "There's a... 30% chance it's already raining")
Cut a Slice, Take the Rest: During the time when Regina is unknowingly being manipulated into gaining weight, she can be seen cutting off the end of a loaf of French bread and biting the loaf. Tina Fey notices this on the first time during the DVD Commentary and actually remarks that Bugs Bunnyused todo that.
Dance of Romance: Subverted with Damian, then almost immediately played straight with Kevin.
Dawson Casting: Regina George is played by Rachel McAdams, who, at 27, was closer in age to the actress playing her mother (32-year-oldAmy Poehler) than she was to the 16-year-old Regina. Also, Lacey Chabert and Lizzy Caplan were both 21 when the film was made. Lindsay Lohan and Amanda Seyfried, however, were both teenagers at the time.
Justified, in that the moment is used for Cady to reflect that she has to beat Kraft with her skills, rather than putting her down for various fashion flaws.
Eating Lunch Alone: Occurs with Cady twice: on her first day of school, when she hasn't made any friends, and after she's been kicked out of the Plastics and rejected by Janis and Damian.
Even the Girls Want Her: Regina. Cady is also shown to have this kind of appeal later on as well.
Friendship Moment: Played straight with Janis's art, and played for laughs (though also rather sweetly) with Karen catching Gretchen in the circle of trust.
Funny Background Event: During Cady's phone call with Regina, you can see Regina's little sister watching Girls Gone Wild and lifting up her shirt while cheering.
Girl Posse: The "Plastics" (Regina, Karen, Gretchen, and later Cady) are unusually well-developed examples. There's also Trang Pak and her "Cool Asians".
Arguably before that, when Cady takes the blame for the Burn Book.
Hey, It's That Guy!: The Janitor apparently has quite a normal home life that he obviously likes to keep on the down low.
Hidden Depths: At the end it's revealed that Gretchen either speaks Vietnamese fluently or is a quick study.
As a native Vietnamese speaker, I can tell you that whatever she's speaking isn't Vietnamese, and the Cool Asian girl's reply to her gibberish ("Cai gi?") translates to "What?"
There's also the scene where she confesses to Cady that she's secretly miserable as Regina's friend and has to pretend to like and not like certain things to get Regina's approval.
Hollywood Pudgy: Regina "balloons" up to a size 6. Though at the height of her weight gain, the special effects crew did shove a pillow up under her shirt. When Regina bumps into a fat girl and she says, "Watch where you're going, fatass!" Regina has very obvious padding on her ass. Arguably intentional, to show how high Regina's standards are.
Tina Fey comments on this commentary and notes that Regina at her fattest in the movie is probably around Tina Fey's own weight.
Important Haircut: Offscreen. After Regina spread the rumor in middle school that Janis was a lesbian, Janis dropped out of school for the rest of the year; when she returned in the fall, "all her hair was cut off, and she was totally weird."
Karma Houdini: Janis, who, despite influencing and encouraging Cady to join the Plastics specifically to damage Regina, gets zero comeuppance when she reveals it to the entire crowd of girls following the revelation of the Burn Book. In fact, she gets applauded for it!
You could argue that everyone thought Janis had been punished enough by Regina's actions from middle school.
Kissing Cousins: At the Halloween party, Karen talks about how hot her cousin is. When confronted, she says, "But he's my first cousin."
Lucky Translation: Karen goes to the Halloween party dressed as a sexy mouse. In the Italian version, when asked what she is dressed as, she answers "Sono una topa". "Topa" means "female mouse", but is also a slang word for female genitalia and a rude compliment to a pretty girl.
The Makeover: Caddy goes from normal student to "plastic".
And in the same vein, it's surely no accident that on many different occasions, a character will mispronounce Cady's name, thinking it's pronounced "catty."
As an aside, Tina Fey later sang a bit of "At Seventeen" in an episode of 30 Rock.
Minion with an F in Evil: Karen seems to be remarkably lacking in actual meanness per se; in nearly all respects she comes across as a good natured ditz. In fact, her only real defining characteristic, besides being the Ralph Wiggum, is that she remains a loyal friend to Gretchen even through Gretchen's Villainous Breakdown.
Gretchen isn't malicious either, just desperately insecure and hungry for attention, which makes her extremely prone to gossip and overdramatize things ("Pusher? Like a drug pusher?"). Makes more sense if you consider that in the original script she was described as ugly.
Misplaced Wildlife: During Cady's party, Aaron sees a picture of Cady back in Africa riding an elephant. An Asian elephant.
No Social Skills: Up until she came to the school, Cady lived in Africa and was homeschooled, thus winding up with absolutely no clue about how things worked in 'Girl World'. Her parents appear to be clueless every time they appear. Here is an unusual case where we get the message via dialogue rather than nonverbally:
Playing Gertrude: 32-year-old Amy Poehler playing the mom of Regina, despite being just five years older than Rachel McAdams. Tina Fey even mentions this in one of the featurettes. Justified, in that a) she's Regina's stepmother, and was probably picked up as a young trophy wife, and b) it's implied that she has had excessive plastic surgery, her "hard-as-rocks" boob job being just the tip of the iceberg.
Popular Is Dumb: Karen obviously, and arguably Gretchen and Regina who seem somewhat unastute. Regina, despite being able to manipulate most of the female half of the school into becoming her pawns, frequently shows herself to be rather Book Dumb.
"Is butter a carb?"
Don't forget that, as a rule of Girl World, you have to dumb yourself down to appeal to boys. It's more than likely that, with the exception of Karen, all the girls are pretending to be much dumber than they actually are.
Professional Butt-Kisser: Gretchen. At the end of the film, Gretchen joins the Cool Asians now that the Plastics have broken up, and attaches herself to Trang Pak the way she did Regina. Her last scene has her brown-nosing in Vietnamese, with her hair straightened to look more like her Asian friends.
Rich in Dollars, Poor in Sense: Regina in a specific example. She could rattle off several mostly-illegal weight loss drugs (most of which either were expensive before being banned or would be expensive to ship from countries where they're still legal.) Yet, she didn't know enough about health and nutrition to know whether or not butter is a carb. It's especially egregious because almost any health class is going to teach nutrition and in general, most teenage girls are so body-conscious that they know more about nutrition than most professional dietitians.
Possibly just a commentary on how American teenage girls obsess over getting thin the fast and easy way rather than via actual healthy living.
In the original script, the Sound Effect Bleep was this, used whenever a character dropped an F-bomb.
Sequel Hook: Averted. The sequel has no recurring characters aside from Principal Duvall. It might appear that the "Junior Plastics" seen at the end are this, but the sequel focuses on a completely different cast of characters.
Shallow Love Interest: Aaron. All we know about him is that he's cute, sucks at math, and used to date Regina. That's it.
Aaron was fleshed out a little more in the original screenplay. Regina complains that he cares about 'his family, friends and school' and there was even a scene with him and Cady where he does the laundry, and explains that he helps out because it's just him and his mom.
Sexy Santa Dress: The skimpy dresses that the girls wear for a Christmas pageant.
Stepford Smiler: Gretchen (the "one small step from a complete nervous breakdown" version, rather than the "empty inside" version).
Stripperiffic: Lampshaded at the Halloween party, where Cady comments on how in Girl World, Halloween is the one night of the year a girl can dress like a total slut and no one can say anything. Gretchen wears a cat costume made of skintight leather, Karen wears a skimpy, cleavage-revealing teddy (only the ears give it away as a costume - "I'm a mouse. Duh."), while Regina wears a "rabbit" costume that's nothing more than a Playboy Bunny suit. Cady, not knowing this and thinking that Halloween costumes are meant to be scary, wears pale makeup, novelty rubber teeth, and a Blood-Splattered Wedding Dress ("an ex-wife").
Too Much Information: "Somebody wrote in that book that I'm lying about being a virgin, 'cuz I use super-jumbo tampons, but I can't help if I've got a heavy flow and a wide set vagina!"
"Let me hear you make some noise!... Settle down."
Wet Sari Scene: How Karen "predicts" when it's going to rain.
What Could Have Been: In the original script Gretchen was envisaged as plain-to-ugly (with a "sniveling whiny face") and part of the in-crowd solely for her wealth. Obviously this was dropped when the very pretty Lacey Chabert was cast in the role but traces of the original perception of the character can still be seen in the film in Regina's obvious surprise that Gretchen was nominated for Spring Fling Queen.
The film was a lot filthier before it was PG-13ified. See Bowdlerization above.
With Friends Like These: Regina to Karen, Cady, and (especially) Gretchen. "Frenemies" indeed!
You Are The New Trend: Regina. One scene has Janis cutting nipple holes in Regina's shirt in the locker room to try and sabotage her wardrobe. Regina wears the top anyway and the next day, every girl has the exact same nipple holes in her shirt.
Artistic License - Geography: In one scene, the characters go to Old Orchard Mall (technically "Westfield Old Orchard"), a Chicago-area mall known for being a large, outdoor mall. Its stand-in was Sherway Gardens in Etobicoke, Ontario, a more conventional indoor mall.
The sequel provides examples of the following tropes:
And later on E! under their "Movies We Love" banner. . .
Broken Aesop: The moral of the story seems to be "don't be a follower," but in the end,Abby decides to attend Carnegie-Melon instead of her original goal of NYU just to stick with Jo, who in turn based her college decision solely on it being the school her dead mother went to.
Chekhov's Gun: The paranoid neighbor. Specifically his security cameras.
He Who Fights Monsters: Tyler points out in one scene that Jo is acting a lot like Mandi.
Hey, It's That Guy!: A lot of the actresses have been featured on Disney Channel at one point (Save for Claire Holt, who was in H2O - Just add water which aired on Nick and TeenNick in the US, but averted in Australia since her show was aired on Disney Channel Australia). That fact doesn't really help matters.
Polite Villains Rude Heroes: Mandi and Tyler (see next trope). Only those two however; Mandi's horrible to everyone else.
Step Sibling Rivalry: Mandi and Tyler, though oddly the dislike comes entirely from his side and Mandi, despite being a bitch to everyone else seems to have some sisterly feeling for him, even declaring him off limits to Chastity and calling his father (her stepfather) "our Dad". He's also the only character she's never directly mean to.
Shout Out: Why does it feel like the football game between the Plastics and the Anti-Plastics is an homage to The Longest Yard (of all things)?
What the Hell, Hero?: When Abby finds out that Jo accepted money to be her friend, she takes it about as well as one would expect.