Bart is shipped off to military school after a particularly destructive prank (lining up 15 police bullhorns and unleashing a soundwave that shatters all the glass in town) -- and Lisa tags along (despite that the military school is boys-only and the other cadets don't take kindly to change) after finding public school education has become a grind.
!!Tropes of this episode: [[YMMV/TheSimpsonsS8E25TheSecretWarOfLisaSimpson YMMV Here]]
* AmbiguouslyGay: Franklyn, the "girliest cadet" before Lisa joins.
* ActuallyPrettyFunny: Homer & Marge laugh when they take Bart & Lisa to the dentist instead of Disneyland.
* BaitAndSwitch: Homer and Marge at the end.
* BadassBookworm: Despite the other cadets hating her because she's not a boy, Lisa loves the military school because it has rigid structure and teachings.
* BeCarefulWhatYouWishFor: Lisa comes to the school looking for a challenge but nearly gives up when confronted with The Eliminator. Bart lampshades this "I thought you wanted a challenge".
* {{Determinator}}: Lisa didnít let the other students, all male, get the best of her. They tried to get rid of Lisa on [[NoWomansLand grounds of her sex]] and proved that she can be just as tough as they are.
** Actually no, they didn't. It just so happened that the semester ended.
*** They never really hated her because of her sex. The only one who actually freaked out over her gender was the Drill sergeant the students were upset about the PositiveDiscrimination given to Lisa on account of her gender.
* ExactlyWhatIAimedAt: Bart hits the first four targets with the grenade launcher at the firing range, and the fifth shot spirals over the horizon out of sight. The instructor points out that Bart missed his last target, but Bart smiles and says, "Did I?" Cut to Principal Skinner back in Springfield standing next to the smoking crater where his car used to be. Made all the funnier by a "Ha-ha!" from Nelson in the background.
* GoneHorriblyRight: Homer and Marge wonder at the end whether or not it's a good thing that Bart now has much more confidence and is trained in several forms of unarmed combat.
* HypocriticalHumour: Following BeCarefulWhatYouWishFor above.
-->'''Bart:''' I thought you wanted a challenge?
-->'''Lisa:''' Duh! A challenge I could ''do''.
* ImAHumanitarian: A mannequin of a woman preparing to eating a baby is shown at the police station:
--> '''Wiggum''': That's right: She's got the "munchies" for a California cheeseburger!
* JackieRobinsonStory/ YouGoGirl: Possibly attempted by Lisa but ultimately subverted. She gets through the semester but the cadets don't change their opinion of her and she doesn't prove better than them at any of the subjects.
* MortonsFork: As Bart and Lisa are forced to do pushups, Lisa is asked "Don't girls like doing pushups in the mud?". Lisa, in turn, asks "Is there any answer I can give that won't result in more push-ups?", to which, after much deliberation by the other cadets, is "No."
* NoodleIncident: Who had the idea of setting up a field trip to the police station?
** Probably Principal Skinner, since Springfield Elementary is so low-rent that a field trip to the police station is all they could afford.
* ParentalFavoritism: Marge and Homer send ''Lisa'' a cassette intended to comfort her yet they don't send Bart anything, not even considering his feelings about how he is at the school. Possibly justified by the fact that Lisa is there by choice, while Bart is there as punishment for causing large amounts of property damage.
* SmarterThanYouLook: Thanks to his years with a slingshot (and the assumption that because he's a public school student, he knows how to handle guns and other weapons), Bart knows how to use a rocket-launcher. In fact, Bart is such a master, he gets Skinner's car from a far distance away.
* StockShoujoBullyingTactics: A rare Western example has Lisa's classmates pretending not to hear her when she asks for help with an out-of-control firearm.
* YankTheDogsChain: When the class is ready to tackle the Eliminator:
--> '''Commandant''': Gentlemen, I regret to inform you that the state supreme court has determined that forcing cadets to cross the Eliminator is a barbaric and malicious practice.\\
'''Lisa''': Yes!\\
'''Commandant''': Hence, you will be the ''last'' class to be subjected to it.