Main characters
Margaret "Meg" Murry
Meg is the oldest child of scientists Alex and Kate Murry, about thirteen years old. Introduced on the first page of the book, she is the story's main protagonist. One of Kate Murry's "abnormal" children, she seems to have a temper and a difficult time focusing in school. She was portrayed by Katie Stuart in the 2003 film and by Storm Reid in the 2018 film.
Charles Wallace Murry
Charles Wallace is the youngest Murry child, at six years old. Charles Wallace speaks only to his family, but can empathically or telepathically read certain people's thoughts and feelings. He was portrayed by David Dorfman in the 2003 film and by Deric McCabe in the 2018 film.
Calvin O'Keefe
Calvin is the third oldest of Paddy and Branwen O'Keefe's eleven children: a tall, thin, red-haired 14-year-old high school junior. He was portrayed by Gregory Smith in the 2003 film, and by Levi Miller in the 2018 film.
Supernatural characters
Hardcover art by Leo and Diane Dillon, showing the "Mrs Ws".Mrs. Whatsit, Mrs. Who, and Mrs. Which
The Mrs. Ws are immortal beings who can travel across large stretches of both space and time by dematerializing and rematerializing ("tessering"). They are all capable of shapeshifting, but appear as elderly women for almost all of the story.
Mrs. Whatsit is the youngest of the Mrs. Ws (despite being 2,379,152,497 years, 8 months, and 3 days old), and has the most interaction with the children. In a past life she was a star, and when reminded, still grieves for the loss of life on her former planets, when the star she was, died.
Mrs. Who communicates by quoting (and translating) literary sayings in Latin, Spanish, Italian, German, French, Portuguese, and Greek. When the Mrs. Ws leave the group on Camazotz, for no immediately obvious reason, Mrs. Who loans Meg her glasses.
Mrs. Which is the leader of the three women, the oldest of them, and the most skilled at tessering. However, she has nearly forgotten what a body is like, so has difficulty maintaining a solid form, and because of this does make a mistake while tessering to Camazotz. She is usually business-like and unemotional towards the children.
IT
Book cover art (1976) by Richard Bober"IT" is the telepathic brain that controls the planet of Camazotz. IT appears as a giant-sized, disembodied human brain, housed in a transparent jar. While IT usually speaks through one of its pawns (such as the Man with Red Eyes) IT can speak directly to people via telepathy. IT is either an avatar or a servant of The Black Thing.
The Black Thing
The Black Thing, a formless, shadowy being, is the source of all evil in the universe.
Secondary characters
Dr. Alexander "Alex" Murry
Alex Murry, the father of the Murry children, is a physicist who is researching tesseracts and their relation to the mysteries of the space / time continuum. At the start of the novel, he has been missing for some time.
Dr. Katherine "Kate" Murry
Katherine Murry, the mother of the Murry children, is a microbiologist. She is considered beautiful by the Murry children and others, having "flaming red hair", creamy skin, and violet eyes with long dark lashes.
Sandy and Dennys Murry
Sandy (named after his father Alexander, also goes by "Xan") and his twin brother Dennys ("Den") are the middle children in the Murry family, older than Charles Wallace but younger than Meg. They are 10 years old and are depicted as inseparable at the time of this book. They are the only "normal" and socially accepted children in the Murry family.
Mrs. Buncombe
Mrs. Buncombe is the wife of the constable in Meg's hometown.
Mr. Jenkins
Mr. Jenkins is Meg's high-school principal who implies that her family is in denial about Dr. Alex Murry's true whereabouts.
Supporting alien characters
Happy Medium
The Happy Medium is human in appearance, but of uncertain gender. She uses her powers and a crystal ball to look at distant places and people. She prefers to look for happy events and her customary demeanor is jolly, but becomes sad upon viewing sad events. She lives in a cavern on a planet in Orion's Belt.
Aunt Beast
Aunt Beast is a nurturing creature who cares after Meg on the planet Ixchel, the next planet out from Camazotz, nursing Meg back towards wholeness after exposure to The Black Thing. "Aunt Beast" is a name created by Meg that the character accepts; her actual name, if any, is not given. She is a human-sized, furry, four-armed, eyeless gray creature with telepathic abilities. Instead of fingers she has numerous long, waving tentacles.
