Matilda Wormwood is a brilliant child. At the age of 3, she teaches herself to read using old newspapers and cooking magazines. Her parents, however, pay little attention to her. She also has a brother, but though he is kinder than her parents, the two rarely speak. Her father is a used-car salesman who brags about selling broken-down cars under false pretenses. Matilda’s mother often ignores her and leaves her home alone. One day, while Matilda’s mother is gone, the then 4-year-old walks to the library, looking for a book to read.
The librarian is surprised to see such a small child come in alone, but Matilda is so bright and well mannered that she is allowed to stay. Matilda reads all of the books in the children’s section, and on the librarian’s recommendation, begins reading Dickens, Hemingway, Steinbeck and other well-known authors.
Matilda’s parents do not support her reading habit, repeatedly calling her ignorant and stupid. When Matilda asks to be allowed to eat in her room and read, her father yells at her to eat in front of the TV like the rest of the family. Matilda, frustrated with her father’s constant neglect and verbal abuse, decides to retaliate in a small way every time someone treats her poorly.
Matilda’s first act of revenge is to put superglue around the inside of her father’s favorite hat before he leaves for work. Her father is unable to remove the hat all day and night. Matilda’s mother finally cuts it off with scissors, leaving her father with several bald patches.
About a week later, her father comes home to find Matilda reading in the living room. In a fit of rage, he snatches the library book, rips out its pages and throws it in the wastebasket. In retaliation, Matilda borrows a talking parrot that can say “hello” and “rattle my bones” from a child in her neighborhood, with whom she is a friend. She stuffs the parrot and its cage into the chimney of her house. Her frightened parents hear the voice and think it’s a burglar before concluding the house is haunted.
Her father comes home one day and instructs his son to work out a sum so the boy can begin learning about business and finance. Matilda immediately figures out the answer in her head, but when she tries to tell her father, he yells at her, calling her a liar and cheat. The next morning, Matilda replaces her father’s hair product with her mother’s platinum-blonde hair dye. Matilda’s father, who is very proud of his black hair, is deeply distressed by the new color.
At age 5, Matilda begins school. Her teacher, Miss Honey, immediately recognizes the child’s brilliance and goes to the headmistress to discuss moving Matilda to a higher grade level. Headmistress Trunchbull refuses, having been warned by Matilda’s father that if anything bad happens at school, it is likely caused by Matilda.
Ms. Trunchbull physically and verbally abuses her students, both in her capacity as headmistress and when she teaches classes. But she does so in such outrageous ways that none of the children’s parents believe the stories. Trunchbull grabs one girl by her pigtails and throws her across a field. A little boy who steals a piece of cake is forced to eat an enormous cake so he will get sick.
Trunchbull takes over one class period of each grade in the school every week. When she teaches, she expects there to be a cup and a jug of water on the desk. Matilda’s friend, Lavender, offers to get the water; however, before Trunchbull arrives, Lavender places a newt in the jug. Trunchbull comes in and proceeds to scream insults at and physically abuse students who answer questions incorrectly. She finally pours herself a glass of water, and out comes the newt.
Trunchbull immediately accuses Matilda and threatens to expel her. Matilda, outraged by this false accusation, wishes that the glass would tip over, spilling the newt onto Trunchbull. She stares intently at the glass, and something begins to happen. She is able to push the cup over with her mind. Matilda is shocked. Since she is unable to go to her parents with the information, she confides in Miss Honey.
Miss Honey urges Matilda to be cautious and invites the child to her home so they can discuss Matilda’s unique gift. When Matilda arrives, she is shocked by how bare and small Honey’s home is and begins to ask Honey about her life. As a child, Honey lived in a fine house with her parents. After her mother died, an aunt came to live with Honey and her father. The aunt was abusive, and Honey’s father died under mysterious circumstances.
A presumably fake will was produced that left everything to the aunt. When Honey got a job, the aunt took all of her wages, saying that since raising Honey was expensive, Honey owes her a great deal of money. Honey is left with one pound per week. Through careful planning, Honey was able to move out of her aunt’s house, but one pound per week is barely enough to live on. Honey then reveals that Trunchbull is her aunt.
Matilda formulates a plan to help Honey. She begins to practice using her powers, and once she is strong enough, she sets her plan in motion. When Trunchbull teaches Matilda’s class, Matilda picks up a piece of chalk with her mind and begins to write on the whiteboard. Pretending to be the ghost of Honey’s father, Matilda tells Trunchbull to leave town and give back Honey’s house and wages. Trunchbull faints, and when she awakens, leaves town after giving back Honey’s inheritance and wages.
After Trunchbull leaves, Matilda is moved to a higher grade and her powers stop working. Honey thinks that Matilda’s extraordinary mind needs a challenge. When Matilda was stuck in kindergarten, all of her excess mental energy needed somewhere to go, which resulted in her developing powers. Now that she is being academically challenged, she has less excess mental energy. Matilda is not bothered by the loss of her powers.
Matilda and Honey remain close friends and spend a great deal of time together. One afternoon, Matilda returns home to find her parents frantically packing. They inform her that they are moving to Spain in less than an hour. Distraught, Matilda rushes to Honey’s house. Honey explains that Matilda’s father has been selling stolen cars and is probably on the run from the law. Matilda begs Honey to allow her to stay. Honey agrees that Matilda can live with her, as long as Matilda’s parents agree. They raise no objection, and Matilda and Honey live together quite happily.