Most parents think highly of their children and (incorrectly) believe their children are geniuses. This is not the case with Mr. Wormwood and Mrs. Wormwood, who have two children, Michael and Matilda. Matilda is a genius, but her parents are counting down the days until they can get rid of her. They’re not impressed when Matilda can speak like an adult by 18 months, or when she asks for books at age four. Instead, they tell her to be quiet and that she’s spoiled if she’s asking for books—she should watch television instead.
Since Matilda is left alone every afternoon, she starts walking to the library every day. The librarian, Mrs. Phelps, points Matilda to English-language classics, like novels by Charles Dickens, Ernest Hemingway, and Jane Austen. As Matilda devours books, she develops a moral compass. So when Mr. Wormwood, a used car salesman, tells Michael about how he puts sawdust in the gear boxes of old cars and runs the speedometers back with an electric drill, she tells him this is dishonest. He scolds her, so Matilda decides she must get back at him. She sneakily puts a line of Superglue in Mr. Wormwood’s hat the next morning, which successfully sticks the hat to his head—Mrs. Wormwood has to cut it off. Then, when Mr. Wormwood tears up one of Matilda’s library books, Matilda borrows a neighbor boy’s parrot and stuffs it up the chimney—her parents believe there’s a ghost in the house. Not long after, as Mr. Wormwood tries to coach Michael through adding up daily profits, Matilda mentally does the math and gets the answer right. In retaliation for her father calling her a cheat and a liar, Matilda replaces some of Mr. Wormwood’s hair oil with Mrs. Wormwood’s platinum blonde hair dye.
Matilda finally starts primary school when she’s five-and-a-half. She goes to the local public school, Crunchem Hall Academy, and is in Miss Honey’s first-form class. Matilda wows Miss Honey in the first few minutes of class by demonstrating that she can read and perform complex mental math. Knowing that Matilda is a genius and needs to be moved up, Miss Honey works up her courage and goes to speak with the formidable headmistress, Miss Trunchbull. Miss Trunchbull is a former Olympic athlete who’s muscular, loud, and hates both children and education. She talks over Miss Honey and refuses Miss Honey’s request to move Matilda up. Miss Honey attempts to speak to Matilda’s parents that evening. She tells them that with some tutoring, Matilda could be ready to attend university soon. But the Wormwoods insist that college is terrible—girls should focus on appearances and getting married.
Meanwhile, at school, Matilda and her new best friend, Lavender, learn about the Trunchbull from older kids. One 10-year-old, Hortensia, earns the girls’ admiration when she tells them about the tricks she’s played on the Trunchbull, such as putting Golden Syrup on her chair or itching powder in her knickers—and the time she’s done in the Trunchbull’s lock-up, the Chokey. Hortensia also shares that the Trunchbull threw a boy out the window for eating in class. Just then, the entire playground watches as the Trunchbull—who hates plaits and pigtails—picks up a little girl with golden plaits named Amanda and throws her into the playing field. The very next day, the Trunchbull accuses a round little boy, Bruce Bogtrotter, of eating a slice of her special cake. To punish him, she makes him eat a whole 18-inch cake by himself while the other students watch. Bruce manages to finish the whole cake, which enrages the Trunchbull.
On Thursday afternoons, Miss Trunchbull takes over Miss Honey’s class for a period. In preparation for her first visit, Lavender offers to fetch and prepare Miss Trunchbull’s water jug and glass. Wanting to impress Matilda and Hortensia, Lavender captures a newt and puts it in the jug. Miss Trunchbull enters Miss Honey’s classroom and immediately begins punishing and tormenting students. For having dirty hands, Nigel has to stand on one foot in the corner; for not being able to give the answer to a math problem, Miss Trunchbull picks Rupert up by his ears. When she finally pours herself a glass of water, the newt plops into the glass. This terrifies the Trunchbull—and she blames Matilda.
Incensed at this injustice, Matilda screams she didn’t do it. But the Trunchbull won’t listen. Angrier than she’s ever been, Matilda sits in silence. She begins to feel peculiar: her eyes feel hot and as though there are invisible arms reaching out of them. With this odd power, Matilda pushes the glass containing the newt over—right onto Miss Trunchbull’s bosom. Enraged but unable to blame Matilda, Miss Trunchbull leaves.
When Miss Honey dismisses the class, Matilda hangs back and tells Miss Honey about her odd power. Miss Honey believes Matilda is telling stories until Matilda repeats the trick. Stunned, Miss Honey invites Matilda back to her cottage for tea. They walk out of the village and down a rural road until they reach a tiny farm worker’s cottage. Matilda is shocked; the cottage looks straight out of a fairy tale, and it’s clear that Miss Honey lives in dire poverty. As they eat their bread and margarine, Matilda asks about Miss Honey’s financial situation. Miss Honey agrees to tell her story.
Miss Honey’s mother died when Miss Honey was two. Her father, a doctor, asked his sister-in-law to come help with Miss Honey—and then he died mysteriously, supposedly by suicide, three years later. Miss Honey’s aunt was abusive and controlling, and things were so bad that Miss Honey was—and still is—too afraid to fight back. Her aunt forced her to do all the housework, and even now that Miss Honey has a job, she takes all of Miss Honey’s paycheck except for a one-pound allowance every week. The aunt lives in the Honeys’ house and, since Miss Honey’s father’s will disappeared, there’s no way for Miss Honey to take ownership of anything. It was Miss Honey’s greatest achievement to find this cottage and move out. Matilda greatly admires her teacher—but she realizes Miss Honey needs help when Miss Honey admits she doesn’t have a bed, and then admits that her aunt is Miss Trunchbull.
Miss Honey walks Matilda to the Wormwoods’ gate. There, Matilda asks Miss Honey three questions: what Miss Trunchbull and Miss Honey’s father called each other (Agatha and Magnus, respectively), and what they called Miss Honey as a child (Jenny). With this information, Matilda concocts a plan. Inside her house, she grabs one of her father’s cigars, places it on her dressing table, and practices using her power to move it every day after school until she can do exactly what she wants to with it.
The following Thursday, when Miss Trunchbull is in Miss Honey’s class tormenting a boy named Wilfred, Nigel shouts that the chalk is writing on the chalkboard all on its own. The chalk writes that it’s Magnus’s ghost, and he asks Agatha to give Jenny her house and paycheck back. Miss Trunchbull turns white and faints—and over the next 24 hours, she runs away. Lawyers contact Miss Honey, who gains ownership of her family’s home, her paychecks, and her father’s fortune. Matilda is moved into a higher form and visits with Miss Honey every afternoon. The two form a close friendship. Matilda’s power disappears, but she’s happy it did.
When Matilda returns home after a visit with Miss Honey one afternoon, Mr. Wormwood informs her that the family is moving to Spain and is never coming back. Matilda races back to Miss Honey’s; she wants to stay with Miss Honey, not move to Spain. Miss Honey agrees to take Matilda if the Wormwoods agree, so they run back to the Wormwood house. Mr. and Mrs. Wormwood agree that leaving Matilda would be one less thing to deal with and don’t look back as they drive away.