The Prime of Miss Jean Brodie is a novel by Scottish writer Muriel Spark, first published in 1961. Set in Edinburgh, Scotland, in the 1930s, it centers on schoolteacher Miss Jean Brodie and her relationship with the "Brodie set," six girls she deems to be the "crème de la crème" of her class at the Marcia Blaine School for Girls. The set includes Monica Douglas, Rose Stanley, Eunice Gardiner, Sandy Stranger, Jenny Gray, and Mary Macgregor.

The novel alternates between the past and the present, circling the question of which one of the girls "betrayed" Miss Brodie. It begins with a group of boys, aged sixteen at this time, talking to the Brodie set. Miss Brodie comes along and dismisses the boys, sharing with the girls the school's latest ploy to force her to resign.

Six years prior, Miss Brodie first gathers the girls and starts imposing upon them an unconventional education. Apart from topics such as the arts, theater, and politics, she also discusses her personal life with them. Once, she tells them about how her fiance, Hugh Carruthers, had perished in World War I.

Miss Brodie leads her students on an exciting tour of Edinburgh's cultural landmarks, ignoring the unemployment lines and praising Mussolini for eradicating such issues in Italy. She criticizes headmistress Miss Mackay's conventional education approach, advocating instead for awakening the innate talents within her students. 

On Sandy's tenth birthday, she has Jenny over for tea. The two are secretly working on "The Mountain Eyrie," a fantastical piece of fiction about Miss Brodie and her deceased fiance. Sandy has an overactive imagination, often conjuring make-believe scenarios to keep herself from getting bored.

The headmistress, Miss Mackay, and most of the staff resent Miss Brodie's unconventional methods. However, two teachers are her vocal supporters—the singing master, Mr. Gordon Lowther, and the one-armed art master, Mr. Teddy Lloyd. Once, Monica alleges seeing Mr. Lloyd and Miss Brodie kissing in the art room. Sandy and the rest of the set find this news exciting and scandalous, as Mr. Lloyd is married with six children.

In late autumn, a supposed ailment forces Miss Brodie to miss school for two weeks. However, when the Brodie set attempts to visit her at home, they find no one there. Sandy and Jenny surmise that Miss Brodie has entered a romance with Mr. Lowther, who lives alone in a mansion in Cramond.

Upon entering their senior year, the girls take the "classical" side over "modern" at the behest of Miss Brodie. This annoys Miss Mackay, who starts trying to win the girls' trust to gain incriminating information on the schoolteacher.

At the end of the Easter holidays, a man exposes himself to Jenny at the Leith River. However, Sandy convinces her not to tell Miss Brodie about the incident. They complete another fictional piece—this time, about Miss Brodie's love affair with Mr. Lowther—and bury the notebook behind a cave.

Even though they are now seniors, the girls continue to see Miss Brodie on Saturdays. She enlists two of them to relay their Greek lessons to her. However, these lessons are soon halted when Miss Brodie takes over the duties of Mr. Lowther's housekeepers, the Kerr sisters.

Insisting that the sisters are starving Mr. Lowther, Miss Brodie fattens him up through homecooked meals over a few weeks. Ellen Kerr is eventually brought to the headmistress to testify that she had found Miss Brodie's nightdress under Mr. Lowther's pillow. However, they lack further evidence to indict her of any inappropriate behavior.

The girls are invited to Mr. Lowther's house in pairs, where Miss Brodie questions...