"The Diary of a Teenage Girl" is a coming-of-age film that follows the life of a 15-year-old girl named Minny living in San Francisco during the 1970s. The story is told through her diary entries, which explore her experiences with adolescence, sexuality, and self-discovery. The film highlights Minny's complex relationships with her friends, family, and her mother's boyfriend, Monroe. It addresses themes of empowerment, identity, and the challenges of growing up, all while capturing the essence of teenage life in a vibrant and relatable way.