Rowell stated that most of the characters have names taken from buildings on the University of Nebraska–Lincoln's campus.
Cather "Cath" Avery : The protagonist of the novel, and title's namesake "Fangirl," Cath is an identical twin and shyer than her sister. Cath is a talented writer, and her hobby is writing fan fiction. In her family, Cath is close to her father and sister.
Wren Avery : Wren is the more confident and less responsible twin. Wren cares about fitting in and partying more than her studies or looking after herself. Wren is described by Cath as having had many boyfriends. After experiencing alcohol poisoning, she agrees to change her ways.
Levi Stewart : Cath's friend and, ultimately, boyfriend. Levi is tall, blonde and comes from a farming background, hoping to eventually work on his family's ranch. Cath describes him as having a smile for everyone, being polite, smart and an extrovert. Before the events of the book, he and Reagan dated, but split up once he discovered her cheating. Levi is shown to be faithful and loyal, and tries to get Cath to come out of her shell.
Reagan : Cath's roommate. Reagan is sarcastic, cynical and often mean to Cath, although this is apparently the way she shows affection. She eventually befriends Cath.
Arthur Avery : Cath and Wren's father. Arthur is
bipolar. He is described as a marketing genius. In the middle of the novel, he suffers from a bipolar episode and is committed to a mental institution. He is an accepting parent and lets his daughters make their own decisions.
Laura Avery : Cath and Wren's mother. She left the girls when they were 8, promising to keep in touch, but did not. She attempts contact with the twins throughout the novel, but is only given a chance by Wren, as Cath resents her.
Nick Manter : Cath's classmate and partner in a
creative writing assignment. Cath describes him as looking like "someone with a steerage ticket on the
Titanic".
Professor Piper : Cath's writing professor. She is described as a small woman with long brown hair streaked with grey, and high cheekbones. She believes in Cath's writing talent and lets her take the semester to work on her final assignment. Professor Piper disapproves of fan fiction and criticizes it as unoriginal. ==Reception==