It is a fact of life that, inevitably, the Alpha Bitch has her moment of comeuppance. Just when this moment occurs, the last person you would expect, someone who has always been a loyal member of the Girl Posse, becomes The Starscream and turns on the Alpha Bitch at the perfect opportune moment, inadvertently aiding the heroes in the process.
Sometimes, this is to take the Alpha Bitch's place in her own right. Sometimes, the backstabber suddenly comes to the realization that the Alpha Bitch is simply a miserable human being, and not worth the loyalty. Sometimes the backstabber is motivated by some form of revenge, jealousy, or ambition. Whatever the reason why, the backstabber's actions will aid the story's heroine (who is inevitably an outcast and the target of the Alpha Bitch's derision). Thus, the backstabber ends up doing the heroine's dirty work without the heroine having to get her hands dirty taking down the Alpha Bitch on her own. The backstabber often never realizes this, and such a result is frequently the furthest thing from the backstabber's mind when she moves to betray the Alpha Bitch. However, the backstabber often won't object to the heroine benefiting, as long as the Alpha Bitch is made to suffer.
Sister trope to The Dog Bites Back (with which it can overlap if the Alpha Bitch is dumb enough to abuse her own posse) and Et Tu, Brute?. Also sometimes overlaps with The Starscream, though it is much more frequent that Backstabbing the Alpha Bitch comes out of nowhere and the Starscream is usually obvious from scene one. (And if the Alpha Bitch in question is really a Lovable Alpha Bitch, that makes this character an Evil Chancellor.) Contrast Professional Butt-Kisser.
- In Revolutionary Girl Utena, the Alpha Bitch Nanami gets backstabbed by her Girl Posse (Keiko, Aiko and Yuuko) as part of her breakdown. The Starscream girl member (Keiko Sonoda, the one with Girlish Pigtails) remarks that it felt good to finally tell Nanami how they all felt about her, that they had gotten tired of exploiting her popularity, and then takes over the gang. Nanami's recent treatment of the girl, based in jealousy, didn't exactly help her.
- This happens to Manami in Life, when one of her Girl Posse tells the teachers about her bullying. This causes Manami to bully her, to the point where she attempts suicide.
- Tia from Saved! waits until the prom to destroy Hilary Faye's reputation by proving that she performed the vandalism on the school for which the heroine was blamed.
- Heather Duke from Heathers: After Heather Chandler's death, Heather Duke quickly becomes the new queen bee. Of course, Heather Duke morphs into this role herself rather quickly.
- Lisa Luder in Romy and Michele's High School Reunion waits until the reunion before confronting queen bee Christy Masters. Lisa seems to be motivated more by moral outrage and personal dislike of Christy than traditional jealousy. The flashbacks show Lisa had always been a more independent thinker than the rest of the group.
- Cady in Mean Girls is an odd case of the heroine doing her own knifing. Jo Mitchell has this happen to her in the sequel.
- Jaqueline, the "ugly" stepsister in Ever After, rebels against her mother and sister's shameless vampiness after realizing they considered her just barely higher on the family's totem pole than Danielle (who they had made a servant in her own home and denied all happiness) and after being casually dismissed as never being able to attract any royal's attention at the ball ("You're only going for the food"). She wisely decided to help Danielle dish them out a karmic comeuppance. She's also the one who patched Danielle up after the whipping and expressed the opinion that her mother and sister had crossed a line, well before there was any profit for her in doing so. She also showed disgust when Marguerite tried to steal Danielle's mother's dress early in the film, so it is clear she sympathized with Danielle from the get-go.
- Tiara Gold in High School Musical 3 does it to Sharpay, but it ultimately backfires.
- From Amanda Bynes' Sydney White, a modern retelling of "Snow White", sorority president Rachel Witchburn, after much verbal and emotional abuse to several people, including her sorority sisters, finally got stripped of her presidency and her regime by said sisters.
- In Happy Death Day, while stuck in a "Groundhog Day" Loop where every day ends with her death, protagonist Tree at one point demonstrates her decision to get over her own 'Alpha Bitch' status by tipping chocolate milk over the head of Danielle, the leader of her sorority (although it technically doesn't count as this was not Tree's final 'loop', with the result that Tree's the only one who even remembers this happened and Danielle continues as per normal once time progresses beyond this day).
- In The House Bunny, the Zetas are just one pledge short of the minimum, so the Alpha Bitch demands they be shut down. Just then, her much-abused friend decides she's finally had enough of being belittled and punched in the chest, and announces that she will pledge Zeta as well. (Made all the more satisfying when the Alpha Bitch is herself punched in the chest at the end of the scene!)
- In Jawbreaker, just as Courtney is being crowned prom queen, she gets her comeuppance when her ex-friends broadcast over the sound system her confession to killing Liz.
- Anastasia from Cinderella III: A Twist in Time does this to her mother Lady Tremaine. Not only that, but she goes full Calling the Old Man Out on her mother, calling her out for not letting her have her own life and illusions and having tried to use her in her plans before.
- In 8 Simple Rules, one of the sisters explicitly invokes this trope.
- In Glee season 2, former head cheerleader and Alpha Bitch Quinn tells Coach Sue Sylvester of New Cheerleading Captain Santana's boob job to get Santana demoted and put herself back on top.
- This trope is a major plot point in the early 1990s Canadian teen soap opera Hillside (broadcast on Nickelodeon as Fifteen and starring a young Ryan Reynolds). The Alpha Bitch is the manipulative, conniving Brooke, who lusts after Hillside School's star athlete Matt and dedicates her life to trying to break up his relationship with "Little Miss Perfect" Ashley (played by Laura Harris). Little does she know that her own BFF and Beta Bitch Kelly (played by future anime voice actress Enuka Vanessa Okuma) has her own plan to ruin Brooke, and is even involving Brooke's own sister...
- Buffy the Vampire Slayer: Harmony does this to Cordelia, after it becomes public knowledge that she's been dating Xander. Arguably an Inversion, however—Cordelia was a Lovable Alpha Bitch by this point, while Harmony really had no such depths. (She eventually gained some, but only after graduating, becoming a vampire and transferring to Angel.
- Kamen Rider Fourze has Miu being attacked and sabotaged by one of her Girl Posse in a beauty pageant. The latter became a zodiart monster, too.
- In Gossip Girl, Penelope constantly is doing this to Blair.
- In the finale of Power Rangers Lightspeed Rescue, Diabolico does this to Queen Bansheera, helping Carter out of the Shadow World portal and closing the lid for him, while taking Bansheera into the Shadow World.
- On Monday Night Raw, Candice Michelle turned on Torrie Wilson, the defacto leader of "Vince's Devils", after Wilson's efforts to help Michelle win the WWE's Women's Championship backfired. That's right, the alpha bitch was brought down by trying to do something nice.
- After Angelina Love got deported, the remaining Beautiful People went to the Knockout Tag Team Champions Sarita and Taylor Wilde to apologize for every bad thing they had done in TNA, saying it was all Angelina's fault. We were then introduced to Lacey Von Erich, Angelina's "replacement", who immediately joined Velvet Sky and Madison Rayne in assaulting Taylor Wilde and Sarita. When Angelina Love did return to TNA, well she didn't appreciate being scapegoated and "replaced" and back stabbed her former stablemates.
- The Most Popular Girls in School: Season 4's main plot is Brittnay doing this to Mackenzie. After 8-and-a-half years, she's had enough of her. They reconcile at the end.
- Coming Up Violet, swapping the spiked and non-spiked drinks.
- Happens to Azula from Avatar: The Last Airbender during "The Boiling Rock", when Mai and Ty Lee turn on her. As Azula thought she held total command over them, their betrayal makes her paranoid of everyone she commands, and is one of the contributions to her Villainous Breakdown.
- In the Recess episode "Outcast Ashley", Ashley B. and the other two Ashleys kick Ashley A. out of the clique for forgetting "Purple Day" (the anniversary of the day they first met where they all wear purple; Ashley A. was wearing yellow), and so Ashley A. decides to hang out with Gretchen for a while. However, the other Ashleys end up befriending her, and then in the end, they leave Gretchen behind and Ashley A. returns to the group.
- In the My Little Pony: Friendship Is Magic episode "Crusaders of the Lost Mark", Silver Spoon turns against Diamond Tiara after being treated badly one too many times. It's this little bit that sends Diamond spiraling towards a long-awaited HeelFace Turn.
- Roxy does this to Pizzazz in the Jem episode "Roxy Rumbles". After Jetta and Pizzazz make fun of her due to her inability to read she calls them out and quits the band. She ends up returning a few days later due to her contract.
- In the Total Drama Island episode "Paintball Deer Hunter", Beth betrays Heather by shooting her repeatedly with a paintball gun after being bullied and bossed around by her for the entire season. Lindsay, Heather's other stooge, even joins in on the fun. Sadly, Beth is voted off soon after and Lindsay goes right back to working for her again...up until "That's Off the Chain" where Lindsay is eliminated, but nonetheless delivers her a "The Reason You Suck" Speech so epic that most of it is bleeped out.