Grinch is a mean old creature who dislikes Christmas and any other festive holiday. He lives in a mountain cave somewhere north of a town called Whoville, where the Whos are preparing for Christmas. It's Christmas Eve, and the Grinch can’t stand the thought of sitting through another Christmas with children noisily playing and people gathering to sing, so the Grinch tries to stop Christmas from coming to Whoville.

Grinch thinks that Christmas is all about the decorations and gifts, so he decides to simply steal every Christmas decoration, tree, and gift. He dresses up like Santa and takes his sleigh down to Whoville. He breaks into every house in Whoville through the chimney, and starting with the Christmas stockings, he takes away every Christmas thing, even the food.

There was one little girl, Cindy-Lou Who, who caught the Grinch stealing Christmas. She thought he was Santa and asked him what he was doing. Being quite sly, Grinch told her that he was taking the tree back to his shop to fix the tree lights.

The Whos wake up on Christmas morning to find their town stripped of all material possessions. To the Grinch's surprise, however, the Whos join hands and begin to sing in celebration of Christmas. Despite his efforts, the Grinch realized he hadn’t stopped Christmas at all. He realizes that Christmas is more than just big dinners, presents and decorations, and that the true meaning of Christmas is love, family, and friendship.

Witnessing the Whos' genuine joy and love for one another, the Grinch undergoes a change of heart. His shriveled heart grows three sizes that day. Overwhelmed with a newfound understanding of the true meaning of Christmas, the Grinch returns all the stolen items to Whoville. He joins the Whos in their festivities, and the story ends with the Grinch carving the roast meat, and enjoying Christmas dinner with the Whos.