The main similarity between the book and the movie "The Outsiders" is that both follow the same storyline. The movie characters have similar roles to the book characters, and Ponyboy serves as the narrator in both pieces. The major difference between the book and the movie is that there is minimal character development in the movie, and the viewer is unable to become more familiar with the characters.
According to CliffNotes.com, other differences between the movie and the book extend to scenes in the movie that are much shallower in detail than in the book. Soda and Darry are depicted as minor characters in the movie, as is the case for the rest of the gang, whose roles are underdeveloped. The impact of Dally's death is lost in the movie, because the viewer barely knows him. This is also the case with the character of Johnny, whose death is symbolic and marks a turning point in Ponyboy's life within the book. Johnny wants Ponyboy to tell Dally certain truths about life, which was the main reason why the story is written for all the Dallys in the world. Although both the movie and the book begin and end with the same words, only the reader understands the full meaning of the words.