Sandy is a highly perceptive and imaginative student at the Marcia Blaine Day School for Girls. She possesses a vivid inner life, frequently carrying on mental conversations with fictional characters from the novels she reads. Though deeply embedded in Miss Brodie's special set and chosen as a confidante, Sandy maintains a sharp, independent streak that allows her to observe her teacher's methods with increasing clarity.

Miss Brodie is a middle-aged, unmarried schoolteacher who proudly insists she is living in her "prime." She blatantly ignores the school's approved curriculum in favor of teaching her students about Italian art, the rise of fascism, and her own romantic history. She carefully cultivates a group of favored students, intending to mold them into an elite group that will carry her influence forever.

Mr. Lloyd is the senior art teacher at the Marcia Blaine School. He is a married man with six children who lost an arm fighting in World War I. He possesses a sophisticated manner and an artistic temperament, harboring an intense fixation on Miss Brodie that bleeds visibly into all the portraits he paints.

Rose is a tall, blond student in the Brodie set who is famous among her peers for being sexually alluring. Despite her reputation, she is a practical tomboy who has little actual interest in romance or sex, preferring cars, trains, and climbing. Her striking appearance makes her a frequent model for the art teacher and a central figure in Miss Brodie's personal plans.

Mary is an awkward, shy, and academically struggling member of the Brodie set. She serves as the group's perpetual scapegoat, bearing the brunt of Miss Brodie's impatience and the other girls' dismissive attitudes. She is easily frightened and often fails to understand the social dynamics playing out around her.

Jenny is a graceful aspiring actress and Sandy's closest friend during their early school years. She shares Sandy's intense curiosity about the adult world and Miss Brodie's private life. She frequently engages in imaginative play, attempting to piece together the mysteries of romance and sexuality.

Monica is a school prefect and a mathematically gifted member of the Brodie set. She is highly observant and unafraid of conflict, famously claiming to have witnessed a scandalous moment between Miss Brodie and Mr. Lloyd in the art room.

Eunice is the athlete of the Brodie set, excelling in swimming and gymnastics. While she participates in the group's activities, she harbors a secret desire for a more conventional life than the extraordinary path Miss Brodie envisions for her students, eventually preferring to join the Modern side of the senior school.

Miss Mackay is the traditional, pragmatic headmistress of the Marcia Blaine Day School for Girls. She sees education as the rigorous instilling of facts rather than the drawing out of innate knowledge. Deeply suspicious of Miss Brodie's influence, she constantly interrogates students in hopes of finding a legitimate reason to dismiss the controversial teacher.

Gordon Lowther is the school's music and choir teacher. He is a small man with short legs, red-gold hair, and a passive demeanor. He owns a large, elegant home in Cramond and becomes entwined in a strange domestic and romantic dynamic with Miss Brodie, who takes over cooking enormous meals for him.

Joyce Emily is a wealthy, troubled new student who desperately wants to join the infamous Brodie set. Because the other girls ignore her, she falls directly under the influence of Miss Brodie, who encourages her reckless desire to seek out conflict.

Miss Lockhart is the science teacher at the senior school. She is described as beautiful, calm, and highly capable. Her explosive classroom experiments and practical demeanor earn the genuine respect of the students.

Deirdre is Teddy Lloyd's gregarious, bohemian wife. She manages a large, loud household with six children and forms friendly acquaintances with the schoolgirls who visit her husband's attic studio.

Ellen is one of two sisters who teach sewing at Marcia Blaine. Easily flustered and lacking classroom authority, she prefers to simply do the students' sewing for them. She eventually takes on housekeeping duties for Mr. Lowther, where she falls under Miss Brodie's strict supervision.

Alison is the sister of Ellen Kerr and a fellow sewing teacher at the school. Like her sister, she avoids criticizing academic instructors and easily defers to Miss Brodie's authority when taking over Mr. Lowther's domestic chores.

Miss Gaunt is a thin, extremely strict substitute teacher who insists on complete silence in the classroom. She has strong ties to the local parish church and holds a particular distaste for Miss Brodie and her special set of students.