Cady's intellectual and justice-driven friend, who is connected to the Sinclair family through his father's relationship with Cady's aunt; his assertive nature makes him stand out in the family.

Cady's kind-hearted cousin, known for her generosity and part of a close-knit group called the "Liars."

Cady's caring cousin, who enjoys playful activities like playing with Legos, and is part of her close circle of friends.

Cady's mother, who embodies the Sinclair ideal of maintaining appearances, but also deeply cares for Cady and plays a crucial role in her recovery.

The patriarch of the Sinclair family, known for his financial power and strict adherence to family ideals, but also displays moments of openness.

Cady's grandmother, noted for her beauty and association with wealth, with limited presence in the story.

One of Cady's aunts, known for instigating family conflicts over property and inheritance issues.

Johnny's mother, who struggles with the aftermath of family tensions but is also involved in disputes over property.

Bess's children, known collectively as the "Littles," who each exhibit varying characteristics and interactions with Cady.

Gat's father and Carrie’s partner, who works in New York and feels unwelcome by the Sinclair family, underscoring the family's complex relationships.