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.
The classroom scenes were shot at Lincoln Middle School in Alameda, CA. Although the film crew were 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.
When Minnie and Kimmie travel to see The Rocky Horror Picture Show (1975), they meet two drag queens outside the cinema. The taller of the two is Joshua Grannell, a popular San Francisco film-maker and drag queen who performs under the name "Peaches Christ".
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.
One scene features Minnie and Kimmie at a bar, where they take two boys into the restroom. The scene was shot at The Alley, a piano bar in Oakland, CA. At the end of principal photography, the bar was also the location of the wrap party for the cast and crew.
Director Marielle Heller makes a small cameo in the movie. When Minnie visits the comic shop, the cashier points out Aline Kominsky signing comics, and the camera quickly shows her sitting at a table, played by Marielle.
In keeping with the film's theme of sexual liberation in San Francisco, Alexander Skarsgård dressed fully in drag for the film's San Francisco premiere at the Castro Theater. Legendary drag queen Cousin Wonderlette was hosting the premiere, and beforehand was talking about her wigs and her outfit, which made Skarsgard feel suddenly disappointed about simply dressing in a gray suit, so he asked if he could join in the fun and dress up as a woman himself; she said yes. His costume was inspired by Farrah Fawcett, and he has since said that his strict physical regimen for The Legend of Tarzan (2016) was nothing compared to the pain of wearing his high heels for a few hours.
Minnie's apartment was shot in the same Haight Street house that was used as Harvey Milk's apartment in Milk (2008), as the main San Francisco residence in Big Sur (2013), as well as Patrick's apartment in the television series "Looking" (2014).
Another coming of age film released two years earlier, The Perks of Being a Wallflower, has a remarkably similar poster design. Also, both films involve characters going to see The Rocky Horror Picture Show.
Phoebe Gloeckner: In the scene where 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 Phoebe 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.