A woman who lives in the same neighborhood as Rachel, whose life events unfold in a non-linear timeline. Her story intertwines with Rachel's and plays a significant role in the unfolding mystery.

Rachel's former husband's current wife, who provides an alternate perspective on the central events. She experiences tension due to her awareness of Rachel's presence and her own complicated marriage.

Rachel's ex-husband and Anna's current husband, crucial to the relationship dynamics in the story. His interactions with the women reveal various layers of conflict and deception.

Megan's husband, whose actions and relationship with Megan add to the story's suspense. His character is explored through his connection to Megan and the unfolding events.

Megan's therapist, whose professional and personal interactions with her add complexity to the narrative. His role is pivotal in exploring Megan's psychological dimensions.