Spinelli dedicates Stargirl in part to philosopher, anthropologist, and educator Loren Eiseley, who, Spinelli says, “taught us that even as we are, we are becoming” (i). This quote expresses one of Spinelli’s major themes in the novel: the idea that our identities continually develop and grow, just as Stargirl changes her name as she matures and learns more about herself. The two main characters in Stargirl are at different stages in their becoming. Stargirl and Leo present a contrast in emotional development.

Stargirl is secure in her current identity. Arguably, she is already her “best self.” She fearlessly embraces life and follows her joy. Stargirl does not care what others think of her and does not need others to like her. She knows and likes the person she is. Stargirl is confident enough in herself to erase her individuality and remove the boundary between herself and others to become one with the universe. She stays true to herself and her beliefs. She has few friends, but the ones she chooses are individuals whom she values and who value her: her family, Dori, Archie, Leo, Cinnamon, and Señor Saguaro (134). Stargirl values substance over appearance. Despite her confidence in her own identity, Stargirl has a lot of room for personal growth.