A top biologist known for his intimidating demeanor, who reveals a gentler side in his interactions with Olive, showcasing a unique personal connection.

A colleague of Adam's at Harvard, who outwardly seems charming but struggles with jealousy and fear, impacting his behavior in the academic environment.

Olive's Vietnamese descent best friend and fellow graduate student, who inspires the fake-dating scheme and embodies dedication and connection.

A professor at Stanford and Adam's closest friend, who provides guidance to Olive and represents a loyal and dependable figure.

Olive's roommate and best friend, who balances life outside of academia and becomes romantically involved with Holden.

Olive's ex-boyfriend, whose past relationship with Olive acts as a catalyst for the fake-dating plan, connecting Olive's present narrative to her previous experiences.

Although not present in the book's events, she significantly influences Olive's motivations and dedication to her scientific research.

Olive's retiring advisor, known for her supportive nature among her graduate students, offering a contrast to other harsher figures within academia.