Julian is a fifth grader who comes from a wealthy, highly protective family. He feels confident talking to adults but struggles secretly with intense night terrors and anxiety. His inability to cope with his fears leads him to lash out and attempt to isolate those who threaten his social standing.

Christopher is an angsty, forgetful fifth grader who recently moved to Bridgeport, Connecticut. He is struggling to adjust to his parents' recent separation and feels overshadowed by family disruptions. He plays electric guitar and is trying to figure out complicated school cliques while maintaining his oldest friendships.

Charlotte is a small, passionate fifth grader with short blond hair who loves dance and dreams of performing on Broadway. She tries hard to stay neutral in school conflicts and avoid negative attention. Beneath her eager, chatty exterior lies deep insecurity about her social standing.

Auggie is an eleven-year-old boy born with a genetic condition that causes facial differences. He is kind, intelligent, and forgiving. His entry into mainstream middle school profoundly impacts the lives, friendships, and perspectives of his peers.

Sara Albans, known as Grandmère, is Julian's fashionable, culturally sophisticated grandmother living in Paris. Unlike Julian's parents, she refuses to coddle him and instead uses her own powerful childhood experiences during World War II to challenge his perspectives.

Melissa is Julian's wealthy, intensely protective mother who serves on the Beecher Prep board of trustees. She attempts to shelter Julian from any discomfort, going so far as to digitally alter school photos to remove things that cause him anxiety.

Jules is Julian's father, a successful New York City lawyer who grew up in Paris. He prioritizes his family's reputation and is initially quick to threaten legal action against the school to protect his son from disciplinary consequences.

Lisa is Christopher's mother, currently separated from her husband and managing single parenthood in Bridgeport. She is stressed and occasionally disorganized but deeply loves her son and tries to maintain her family's longstanding ties to the Pullmans.

Angus is Christopher's father, who commutes and splits custody after separating from his wife. He tries to comfort his son and be supportive during family emergencies, though he sometimes overlooks the depth of Christopher's anxiety.

Mr. Tushman is the principal of Beecher Prep. He prioritizes kindness and assumes his students are capable of maturity, actively guiding them toward empathy and recognizing their positive community contributions.

Summer is an authentic, kind fifth grader who famously sat with Auggie on the first day of school. She bonds with Charlotte and Ximena over their dance performance and their shared connection to a local accordion player.

Ximena is a highly intelligent, wealthy student whose parents work for the United Nations. She initially aligns with the popular clique and appears snarky, but her frequent moves around the world hide a desire for genuine connection.

Maya is a loyal friend to Charlotte who struggles to understand complex middle-school social cues. She views people in absolute terms of good or evil and reacts impulsively when she feels her friends are being mistreated.

Mrs. Atanabi is a fun and energetic but exacting dance teacher at Beecher Prep. She choreographs a meaningful performance for Charlotte, Summer, and Ximena, using music that holds deep personal significance to her.

Jack is a fifth-grade student at Beecher Prep who overcomes initial hesitation to become genuine friends with Auggie. His loyalty leads him into a physical and social conflict with his former friend Julian.

Ellie is Charlotte's former best friend who drifts away when she is invited to join the more popular social group. Her changing allegiances create a ripple effect of hurt feelings among her old friends.

Savanna is the recognized leader of the popular girls' clique at Beecher Prep. She is often condescending to those outside her circle and resents Charlotte for earning a spot in the dance performance.

Gordy is a blind man who plays the accordion in the neighborhood. His sudden disappearance distresses Charlotte, and the quest to uncover his whereabouts serves as a bonding point for several girls at school.

Mr. Browne is a perceptive English teacher at Beecher Prep. He maintains correspondence with Julian over the summer, gently challenging him to reflect on his actions and encouraging his personal growth.

Isabel is Auggie's loving mother. She is emotionally perceptive and notices Christopher's deep distress during a video call, providing him with much-needed maternal comfort when his own family is in crisis.

Nate is Auggie's father, a warm presence who brings joy to his family, notably by adopting their beloved dog. He helps maintain the close-knit, supportive environment that Auggie relies on.

Via is Auggie's older sister. She is protective of her brother and occasionally irritated by the younger boys' energetic space-themed games.

John is a fourth grader in the after-school band who is socially awkward and unfamiliar with the popular songs the older kids want to play. He relies on Christopher's friendship in the band.

Elijah is an older, more confident boy in the after-school band who pressures Christopher to ditch his less popular friend in order to form a new music group.