Anne is a 13-year-old Jewish girl forced into hiding in a secret annex in Amsterdam during the Nazi occupation. Her high energy and constant talking often put her at odds with the adults who expect quiet compliance. She relies heavily on her diary to process the sudden confinement and her confusing journey through puberty.

Margot is Anne's 16-year-old older sister. She recently received a terrifying order to report to a work camp, prompting the family to flee into hiding immediately. Her calm demeanor leads the adults to hold her up as a model of good behavior. She harbors her own private fears alongside a desire to eventually become a nurse.

Edith is Anne and Margot's mother. She prefers to avoid open conflict and attempts to maintain traditional household order in an impossible situation. She bears the stress of hiding quietly but struggles to connect with her headstrong younger daughter.

Otto is the patriarch of the Frank family. He formerly owned the business operating below the Annex and acts as the unspoken leader of the hidden group. He makes final decisions about taking in new residents and mediates disputes between the two families. He maintains a warm, fatherly presence and is highly protective of the group's safety.

Peter is a timid 16-year-old boy adjusting to confinement alongside the Frank family. He frequently retreats to his small room with his cat to escape the bickering of his parents. He initially finds Anne intensely irritating and prefers isolation to her constant chatter.

Miep is a young Dutch woman in her early twenties. She works as a secretary for Mr. Frank's business and takes on the immense risk of securing illegal ration cards. She brings food, library books, and news to the people in the Annex, serving as the group's primary lifeline to the outside world.

Mr. Kraler is a Dutchman managing Mr. Frank's business during the Nazi occupation. He coordinates the logistics of the Secret Annex and warns the residents about potential dangers from the warehouse employees below. He maintains a grave demeanor, highly aware of the constant threat of discovery.

Petronella is Peter's mother. She grew up accustomed to a privileged lifestyle and struggles to adapt to the deprivations of hiding. She frequently complains about the poor food and engages in loud arguments with her husband. She is highly protective of her personal belongings, particularly the fur coat given to her by her father.

Hermann is Peter's father. He struggles with a heavy smoking habit and becomes incredibly short-tempered when his cigarette supply runs low. He is highly critical of his son's reclusive nature and frequently clashes with his wife over their shared anxieties regarding food and survival.

Alfred Dussel is a German Jewish dentist. He joins the Annex two months after the original families and brings terrifying, unfiltered news of the outside world. As a middle-aged bachelor thrust into sharing a room with a teenage girl, he proves to be an inflexible and impatient roommate. He suffers from allergies that make living with Peter's cat a constant irritation.