The classroom scenes were shot at Lincoln Middle School in Alameda, CA. Although the film crew was given permission to shoot in the school, the school staff objected to the content of the script and insisted no filming be done at any time when students could possibly be on campus. As such, the classroom scenes were shot on a single night, with lights outside the windows to give the appearance of daytime.
All the sex scenes between Bel Powley and Alexander Skarsgård's characters were shot in the first week of filming. They had two weeks of rehearsal, discussing the emotional relationship between them, then they just got on set and did it.
Bel Powley's American agent sent her the script and she loved it so much that she sent an unorthodox audition tape: she was doing a scene in Minnie's bed, so she shot it in bed, in her underwear. And then added a separate little bit to the end of the tape talking directly to the camera, talking to Marielle Heller [the director] basically saying how much this film resonated with her, how much it would mean. Heller and Powley Skyped, got on well, and then Powley flew out to New York and met with Alexander Skarsgård.
The film is based on the graphic novel The Diary of a Teenage Girl: An Account in Words and Pictures by Phoebe Gloeckner.
Phoebe Gloeckner: When Minnie meets her mother and Monroe in the bar, Minnie runs out of the booth as the camera momentarily lingers on a brunette woman smoking a cigarette. The woman is Gloeckner, author and illustrator of the original "The Diary of a Teenage Girl" novel. The novel is semi-autobiographical, with the character of Minnie Goetz based on Gloeckner herself.
Marielle Heller: When Minnie visits the comic shop, the cashier points out Aline Kominsky-Crumb signing comics, and the camera quickly shows her sitting at a table, played by Heller.