- Alice is the anonymous protagonist (her name is an allusion to a Jefferson Airplane song) whose intermittent diary entries narrate Go Ask Alice.
An intelligent, sensitive girl with a literary flair, she experiments with drugs and the counterculture to escape from her low self-esteem and consuming loneliness.
in-depth analysis of Alice.
- Alice's unnamed father (a professor) and mother (a homemaker) care deeply about their daughter but are unable to communicate with her openly. They lead a traditional upper-middle-class life.
in-depth analysis of Parents.
- Joel is a working-class freshman at Alice's father's university. His father died when he was young, his mother toils in a factory, and he works as a janitor to pay his tuition. He is gentle in his growing romantic relationship with Alice, spiritual in a non-religious way, and wise about many things, especially loss.
in-depth analysis of Joel.
- Alice's grandparents are beloved members of the family. Alice spends a summer with them, and they visit on holidays up until their deaths.
- Alice's younger siblings—Tim and Alexandria—are better adjusted than she is, which sometimes makes her jealous. Tim develops into a mature young man.
- Chris accompanies Alice on her journey to San Francisco, and the two girls go on and off drugs together.
- Roger is a straight, square boy on whom Alice has an overwhelming crush. He plans to attend military school.
- Sheila is a sophisticated older woman, into drugs and kinky sex, who gets Chris a job in her hip San Francisco boutique.
- Richie is Alice's college boyfriend until she leaves home the first time. She sells drugs to help him someday attend medical school.
- Alice meets Babbie, a young former prostitute and drug addict, in the mental hospital.
- Beth is Alice's Jewish neighbor, a nice girl with whom Alice bonds at first but, after Alice's drug use, Alice finds has changed.
- An affable, fatherly custom jeweler who gives Alice a job. He has a large, robust Italian family.
- The psychiatrist at Alice's mental hospital. He is sympathetic to Alice's case.
- A 14-year-old girl whom Alice meets in Oregon. She has been sexually abused by both her stepfather and foster family siblings.
- A violent drug user at school who tries to get Alice to get him drugs and later becomes her supplier.
- An old drug-using friend of Alice's who threatens Alice when she won't return to her old habits and eventually gets Alice put in the mental hospital.
- A "straight" girl who befriends Alice at the end of the book and accepts her into her group of non-drug-using friends.
- An awkward girl Alice initially befriends when she moves into the new town.
- Richie's college roommate who has a hidden homosexual relationship with him.