Revealing mistakes: When Jenny and Sandy are toasting bread in the fireplace, they grab the ends of the forks that were in the flames. Of course, these would be too hot to touch.
Incorrectly regarded as goofs: Miss Brody presents a slide show to the class. She tells a tale of how Dante Alighieri fell in love with Beatrice Portinari when they met at the old bridge (Ponte Veccio) in Florence. Miss Brody changes some of the facts of the Dante and Beatrice story, but in doing so she is relating the story (consciously or unconsciously) of her own failed romance with an older man.
Continuity: In the scene where Mr. Llyod spies Ms. Brodie and the girls from his studio window he is seen wearing dark brown pants. He rushes from the room. When he emerges on the street he is wearing light colored pants.