* Calpurnia Tate: The young protagonist, a bright and curious girl who is growing up in rural Texas in the early 1900s. She is fascinated by science and nature and is constantly asking questions about the world around her.
* Miss Calpurnia Tate: Calpurnia's grandmother, a wise and resourceful woman who is a strong role model for Calpurnia. She teaches her granddaughter about life, nature, and the importance of family.
While other characters play significant roles in the story, Calpurnia and her grandmother are the central figures, their relationship and experiences forming the heart of the narrative.