Calvin O'Keefe is one of the characters of the A Wrinkle In Time novel.
He is the third oldest of Paddy and Branwen O'Keefe's eleven children, a tall, thin, red-haired 14-year-old high school junior who is not the best in math but has to study to play on the school basketball team, and is one of the popular boys in high school. His mother is a very cranky, tired woman with too many children. Neglected by his own family, Calvin joyfully enters the lives of the Murry family, starting in Chapter Two. He also loves Meg Murry. He shows some signs of being able to communicate telepathically, the same power Charles Murry seems to have, a technique referred to in later books as kything. He also feels as if he has been hiding his true self all his life, and likes the Murry family much more than his own, which is characterized by abuse and dysfunctional dynamics.