Gene Westover is Tara's father, who lives his entire life on Buck’s Peak, Idaho. He is characterized by intense religious fanaticism, paranoia, and a belief in his own authority, which creates a primary conflict for Tara as she pursues her education.

Faye Westover is Tara's mother. Raised nearby, she supports Gene's authoritarian regime while managing household duties and later becoming the family's primary breadwinner through her essential oils business.

Shawn Westover is Tara's older brother, known for his defiance of Gene and his abusive behavior towards Tara and other siblings. His actions highlight family issues and the cycle of fundamentalism.

Tyler Westover is Tara's older brother who successfully escapes the family's restrictive beliefs by pursuing higher education. He becomes Tara’s only family ally after she is cut off by other members.

Audrey Westover is Tara's older sister. She initially rebels against her family's ways but eventually conforms. She plays a significant role when she and Tara confront family issues involving their brother Shawn.

Dr. Kerry is Tara's Jewish History professor at BYU, who becomes a mentor and advocate for her during her academic journey, encouraging her to pursue opportunities at Cambridge.

Luke Westover is Tara's older brother with whom she works in the family junkyard. He suffers frequent injuries but remains kind to Tara despite family estrangement.

Richard Westover is Tara's younger brother, who also leaves home to pursue higher education. He supports Tara's decision to distance herself from the family beliefs.

Tony is the eldest Westover sibling, who distances himself from the family by marrying young and working as a truck driver but eventually returns to work for Gene after his business fails.

Charles is a "normal kid" and Tara's first crush. His interactions with Tara reveal her family's stark differences from others and contribute to her growing self-awareness.

Sadie is a local town girl who dates Shawn. Her relationship with Shawn provides insight into his character and affects Tara’s interactions with him.