The book begins by introducing the Bucket family. In a small wooden house at the edge of a big city live the seven Buckets. Grandpa Joe and Grandma Josephine are Mr. Bucket's parents, and Grandpa George and Grandma Georgina are Mrs. Bucket's parents. Mr. and Mrs. Bucket have one child, a small boy named Charlie, who is the story's protagonist.
The Buckets are extremely poor. The house is too small for all of them, and they only have one bed, which the four grandparents stay in all day. Mr. Bucket is the only one in the family with a job; he works at a toothpaste factory, screwing on toothpaste caps all day, and makes very little money. They eat cabbage stew for nearly every meal.
This is especially hard for Charlie, since he loves chocolate more than any other food in the world, and they live right down the block from the largest chocolate factory in the world belonging to Mr. Willy Wonka. Charlie passes by the factory on his walks to school every morning and wishes desperately that he could go inside.
Every evening, Charlie listens to his grandparents' stories. On one particular evening, Grandpa Joe tells Charlie all about Mr. Wonka's factory. He says Mr. Wonka is the best chocolate maker in the world, and can make anything he wants. Grandpa Joe speaks of all the things Wonka has made, including chocolate ice cream that will never melt. He also tells Charlie a crazy story about Mr. Wonka and an Indian prince named Prince Pondicherry. the prince asked Wonka to build him a palace entirely of chocolate, and Wonka did. Wonka told him when it was finished to start eating right away, but the prince intended to live in it—that is, at least until a very hot day came along and it melted around him.
Grandpa Joe talks more about the mystery of the Wonka factory: nobody ever goes in, and nobody ever comes out. They have never seen any of Wonka's workers, though they know they must exist. Grandpa Joe says he does not believe ordinary people work there, but he saves the rest of that story for the following evening. When he continues, he tells Charlie that not so long ago, there were thousands of regular people working in Wonka's factory, but he made them all leave because some of them were spying for other chocolate makers to get Wonka's incredible recipes.
The factory was dark for days, but then all the sudden it started up again, and all the lights and machines went on. Still, though, no workers came in or out. Observers could see tiny dark shadows in the windows working, but no one knows what kind of people these tiny workers are. As Grandpa Joe finishes the story, Mr. Bucket comes into the room waving the evening newspaper and reveals some exciting news: Wonka will be opening his factory at last to a lucky few.
The whole family gathers around the paper to read. Wonka has decided to allow five children to enter the factory and be escorted around on a tour. At the end of the tour, they will receive a lifetime supply of chocolate as an added gift. The children will be chosen through a search for Golden Tickets. Five Golden Tickets will be hidden inside Wonka's chocolate bars around the globe, and the lucky five children who find it will get the prize. Charlie desperately wants a Golden Ticket, but he only ever gets one candy bar a year on his birthday. Even though his birthday is approaching, he has a terrible chance of finding a ticket with only one candy bar.
A boy named Augustus Gloop, an extremely fat nine-year-old boy, finds the first Golden Ticket the following day. In the newspaper interview, his mother says proudly that she knew Augustus would find one because he eats so many candy bars a day, since eating is his hobby. The Buckets are repulsed by this boy and his family, and wonder who will find the remaining four Golden Tickets.
The entire country begins buying candy like crazy in the desperate search to find the Golden Tickets. A famous scientist insists that he has invented a machine that can detect Golden Tickets inside chocolate bars without opening them, but after the machine grabbed hold of a woman's gold tooth filling instead, it was smashed by the crowd.
On the day before Charlie's birthday, a rich girl named Veruca Salt finds the second Golden Ticket. Veruca's father owns a peanut-shelling factory, so when Veruca announced that she wanted to find a Golden Ticket, he bought a huge supply of Wonka bars and had his factory workers start shelling off their wrappers instead. After a few days, they found one at last. The Buckets are once again displeased with this spoiled child and her family, and Charlie does not think they played the game fairly.
The next morning is Charlie's birthday, and he wakes up to his present: a Wonka Whipple-Scrumptious Fudgemallow Delight bar. Everyone watches in anticipation as he begins to open it, though Mrs. Bucket reminds him not to be disappointed if the ticket is not there. His grandparents remind him that no matter what happens, he still has the delicious bar of candy. At last Charlie opens it... but there is no Golden Ticket to be found. Charlie is upset, but tries to share the candy with everyone else. They refuse, however, since it is his birthday present, and he heads off to school.
Two more Golden Tickets are found that day, the third by a girl named Violet Beauregarde who is a compulsive gum-chewer. When she heard about the contest, she switched from gum to candy bars, then once she found the ticket she switched right back to gum. In her interview, she talks about how she has been chewing one piece of gum for three months straight, beating the record set by her best friend Cornelia Prinzmetel.
A boy named Mike Teavee, who spends all his time watching television, particularly violent shows, finds the fourth ticket. As they read about Mike Teavee, Grandma Georgina asks whether all children these days are spoiled brats like the four who have found Golden Tickets. They assume that the final ticket will also go to a beastly child who does not deserve it.
The next day when Charlie gets home from school, Grandpa Joe has a secret surprise waiting for him. He gives Charlie a ten-cent piece, his secret hoard, to go buy another candy bar so they can have another shot at finding a ticket. Charlie is reluctant to use it at first, but Grandpa Joe convinces him, and he runs to the store and buys a Wonka's Nutty Crunch Surprise bar. Excited, they open it slowly... but once again there is nothing in there but the candy bar.