A victim of bullying is cajoled into taking boxing lessons, usually from a cartoonishly macho alpha-male character. The victim usually ends up finding an alternate, non-violent but always interesting means of dealing with the bully. Oddly, Eastern martial arts (karate or kung fu) are generally considered to be an acceptable way of dealing with bullying. l Krav-maga, not so much.
YuYu Hakusho: Subverted in the manga version; Yusuke, as a ghost, sees a kid he knew in grade school getting bullied. To help him out, Yusuke tries to communicate with him in dreams to get him to stand up for his dream of being a professional boxer and challenge the bully. On the day of the arranged match, however, Yusuke simply possesses the boy's body and beats the crap out of his tormentor.
Ryo Narushima from Shamo learns karate to keep himself alive in correctional facility. It goes downhill from there, to put it mildly.
Played straight and deconstructed in Kenichi: The Mightiest Disciple. Kenichi starts learning martial arts at the Ryozanpaku dojo to protect himself from Daimonji, an Arrogant Kung-Fu Guy. However, beating Daimonji with his newly acquired skills doesn't end Kenichi's problems; he instantly becomes a Fight Magnet for many trained fighters who take notice of his win.
In the film Billy Elliot, the young Billy is sent off to the boys' club to learn boxing, and instead he takes up ballet dancing.
In Rocky V, Rocky's son learns how to box in order to deal with the school bully (though, ironically, not from Rocky himself).
Subverted in The Kid. The main character, who is in his forties, meets up with himself as an eight year old, somehow. In an effort to toughen himself against bullies, he gets his boxer friend to teach him. After the boxer learns it's for bullies he says "He doesn't need boxing, he needs to learn street fighting."
In "The Bells of St. Mary" a student gets boxing lessons from a Nun of all people after the priest praises the other boy for knowing how to fight.
In The Jungle Book, when Baloo first meets Mowgli, the man cub tries to fight him off, but of course his blows are too puny. Taking pity on him, Baloo decides to teach him how to fight like a bear.
In David Weber's novel Honor Among Enemies, a major subplot revolves around a newly enlisted naval rating who's been targeted for violent harassment by a petty criminal in the crew. He refuses to testify that he's being threatened, so a few of the ship's noncoms start giving him martial arts lessons. If anything, this succeeds too well; in their next confrontation, the naval rating injures the bully so badly that he'd be crippled for life if not for the setting's advanced medical technology.
Blossom by Andrew Vachss. Ex-con turned private investigator Burke teaches a young man facing prison how to conduct himself, including a no-holds style of boxing.
In Richard Llewellyn's "How Green Was My Valley", Huw Morgan gets boxing lessons to defend himself from school bullies. His first lesson comes from his father (along with a payment plan for every bruise, bloody nose or split lip Huw comes home sporting). This is not enough, so his older brother gets the valley's professional boxers to train him specially. He gets VERY good at it.
Gaku Homma, a teacher of aikido, has deconstructed this trope in his book Children and the Martial Arts. He recounts one parent wanting to enroll her child for aikido to protect against a bully. Homma explained to her that if her child did hit the bully back, the bully would probably return with a knife...or worse.
Mork in Mork and Mindy unsuccessfully tries to learn how to box from Mindy's father when faced with a bully. (His alternative solution is to use his hitherto unmentioned power of Time Warps which enables him to essentially make everyone move in slow motion while he moves at normal speed which enables him to humiliate the bully.)
First, an early episode had Extroverted Nerd Steve Urkel dealing with a bully. He actually ends up challenging the bully to a boxing match, but having no experience and muscles like wet string, he knows he's in trouble. He convinces Carl to teach him to box. It's pretty much for nothing, though, and he's beaten down. Before the bully can finish him off, though, a spectator protests — and then the whole crowd. The bully backs down in the face of pretty much the entire student body apparently being willing to fight on Steve's behalf.
Second, Richie, a cousin of the Winslows who calls Urkel "Uncle Steve" (though they're unrelated), has trouble with a bully at school. Steve, apparently not remembering his own experience with the same tactic or maybe understanding Richie had more muscle than a quadriplegic orange (unlike him), advised Richie to stand up to him—physically if necessary. Richie got in trouble at school for fighting, and his mother was angry at Steve—until Richie explained that he was defending himself from a bully, at which point it became somewhat accepted.
Third, Richie and a friend had their playground taken over by an adult gang. Steve tried to intervene, but with all the physical prowess of Professor Xavier on Valium, he was pretty much powerless — until he used his Transformation Ray to infuse him, Richie, and Richie's friend with the DNA of Bruce Lee, upon which they went, well, Bruce Lee on the gang's asses...complete with offensive Engrish accents.
Punky Brewster tried, unsuccessfully, to learn to box when a bully was picking on her. Her friends told the bully that even if she beat up Punky, she'd still have to fight all of them, one by one.
The pilot of Burn Notice has the Michael teaching a kid how to defend himself from bullies, using guerilla tactics. The implicit acknowledgment is that he suffered from bullying as a kid (either from his peers or from his father), and wished he had received boxing lessons as a child.
Subverted in Brady Bunch: Peter learns to fight after he has run out of ways to stop a bully from tormenting Cindy. At the end, the bully eventually respects Peter, who has a good left hook punch in his opinion.
In season two of Smallville, tired of relying on Clark to save her, Lana Lang gets a crash-course in self-defense and self-esteem in the form of boxing lessons from Lex Luthor after being harassed by a bunch of thugs.
In Kitchen Nightmares, Chef Gordon Ramsay gives one to a restaurant manager with serious self-esteem issues. It works to say the least.
On The George Lopez Show, Max gets boxing lessons from none other than the professional boxer Laila Ali, daughter of Muhammad Ali.
King of the Hill put an interesting twist on the Boxing Lesson, by having Bobby take a women's self defense course and then dealing a savage groin kick to his tormentors. The trope is subverted nicely when Hank attempts to teach his son how to box, and receives a nasty kick to the testicles when Bobby gets frustrated with the lesson. Then double-subverted when he learns groin kicks do nothing to keep his mother from punishing him note a break from reality.
Inverted in Jackie Chan Adventures where it the bully who seeks help in the martial arts from Jade (who is the would-be victim that happened to kick his ass). After being trained in the "Ancient Art of Butt-Whoop" he becomes the one who stops bullying.
A variant occurs where both Tweek and Craig are taught different fighting styles for their upcoming fight. Jimbo intentionally teaches Tweek dirty boxing techniques (like nut shots) and Craig is taught sumo wrestling.
Also parodied in the episode "You Got F'd in the A" (also serving as a send-up of "You Got Served). The gang is unexpected "served" by a group of out-of-town dancers, leading Stan's dad to give Stan a self-defense lesson — in dancing.
Subverted in The Raccoons episode, "Black Belt Bentley," where Bentley is eager to learn martial arts from Sheaffer when he is bullied so he can smash their heads in. However, when Sheaffer learns of the young Raccoon's intentions, he promptly kicks him out of the class. However, Bentley does not get the message until he gets so psyched up improvising learning from a martial arts film that he inadvertently attacks Bert and breaks his arm. While Bentley is kicking himself for being so stupid, he meets the bullies again. However, chastened by his experience, Bentley uses his martial arts training with appropriate restraint to defend himself while reasoning with the bullies about the original misunderstanding that caused the conflict. The combination of Bentley's explanation and his fighting moves are enough to make peace with the impressed bullies. As a result, Sheaffer not only lets Bentley back into the class, but promotes him to the yellow belt training rank in appreciation of his solid learning and good attitude.
In Phineas and Ferb, Phineas is forced into a fight with Buford the school bully...and he's trained by Evander Holyfield. Yes, it's that kind of show.
When Chicken in Cow and Chicken is bullied at school, Father tells Chicken to take Karate lessons from — who else? — the Red Guy. You can guess the rest.
In Home Movies, Brendon's decrepit grandpa gives him an impromptu boxing lesson to help him deal with an angrily super-competitive goalie. The lesson quickly Crosses the Line Twice as grandpa's boxing gloves are filled with ball bearings for "oomph". When Brendon later encounters the goalie, he tries an alternative means of discussing the goalie's relationship with his overachiever father, and quickly ends up on the ground in an armlock, Eventually, he gets through to the bully, who rejects his father's competitive teachings and becomes a hippie pacifist; leading Melissa to beat up Brendon for "ruining" the bad-boy she had a crush on.
An episode of Garfield and Friends has Jon being thrashed by a mugger while out on a date with Liz. Jon goes for karate lessons to learn how to protect himself. On his next date with Liz, he says that he'd beat up that same mugger if they met again - guess who he runs into? In the end, it's not Jon's karate skills, but Garfield who saves the day.
When Muhammad Ali was young, he had his bike stolen while receiving some freebies inside a building. When he reported the bike stolen, he said to the cop in question that he was gonna find the person who did it and beat them up; the cop told him to go to a boxing lesson, and invited him to come back. He then became the best damn boxer in history.
In Montreal there are several police officers who offer young kids in poor neighborhoods boxing lessons as a mean to get off the street. Boxing is a regulated sport with lots of rules and requires good discipline, so it helps distract kids who like to fight anyway and give them contacts with people who can give them help with getting out of street gangs.