August "Auggie" Pullman:The protagonist. His face is deformed due to "mandibulofacial dysostosis" or "Treacher-Collins syndrome", along with other facial malformations. He faces many difficulties when he enrolls in his first year of middle school after being homeschooled for many years. In the end, he is able to make new friends and accept himself for who he is.
Olivia "Via" Pullman: Auggie's older sister. She talks about Auggie and the hardships of being a sister of someone who is deformed in Part 2. She truly cares for Auggie and will always defend him. Oftentimes Via feels jealous of the attention that Auggie receives because of his deformity. She often scolds herself and feels guilty for feeling this way.
Summer Dawson: One of Auggie's first friends. She sits next to him on the first day of school when no one else would. She didn't care what the other students thought of Auggie, and she was always very kind to him. She tells her point of view in Part 3.
Isabel and Nate Pullman: Auggie and Via's parents. Isabel is a Brazilian woman, and Nate comes from European ancestry. They deeply care about Auggie but will unintentionally leave Via feeling left out. They work with Auggie to make sure that going to private school instead of being homeschooled is ultimately his decision.
Jack Will: August's best friend. He was told by Mr. Tushman along with Charlotte and Julian to give August a tour of Beecher Prep. At first, he did not want to be friends with August because of his facial deformity. He though that it would prevent him from being friends with the "popular kids", but later appreciates him as a friend, for who he is.
Julian Albans: The primary antagonist. He does not like Auggie and tries to convince anyone in the school that if they touch him, they will develop "The Plague." At the end of the story, Julian's parents no longer want him to attend the middle school, as they say that they don't feel that Beecher Prep is an "inclusion school."
Justin: Via's boyfriend. He is initially surprised by Auggie's face but is very kind to him. He has a main part in the play "Our Town" with Via at their high school. In his part in the book, he doesn't capitalize his "I"'s. He also mentions that he has "tics," especially when he is nervous and describes them as "hard blinks" and "the occasional head pull."  This leads the reader to believe that he has a form of Tourette syndrome.
Daisy: Via and August's first dog. She was August's first true friend. She was an old dog, and gets sick towards the end of the novel where she has to be put down. August's family then gets a new dog named "Bear."
Miranda Navas: Via's friend. Via, Miranda, and Ella are friends. Miranda had recently cut her hair into a bob and dyed it pink, and dressed in a manner that she would have never dressed before, and she and Via slowly drifted apart. She took care of August as her little brother, and lied to everyone that August was actually her brother at camp. Miranda and Via become friends again at the end.
Mr. Tushman: The director of Beecher Prep. He is extremely welcoming and positive towards Auggie throughout the course of the school year. He tries his hardest to make him feel welcome at school. He delivers an important speech at graduation where he says "if every single person in this room made it a rule that wherever you are, whenever you can, you will try to act a little kinder than is necessary - the world would be a better place."