A young girl at Hailsham, is described by the narrator as being very bossy at the beginning of the novel. She has a lot of hope for her future and thinks that she will be able to become something other than an organ donor. However, her hopes are crushed as she realizes that she was born to be an organ donor and has no other future. Towards the middle of the novel, Ruth undergoes a transformation to become a more aware, thoughtful person who thinks about things in depth. She is constantly trying to fit in and be mature, often repudiating things from her past if she perceives that it won’t look cool. Thus she threw away her entire collection of art by fellow students, despite it being her prize possession, because she sensed that the older kids at The Cottages looked down on it. She becomes an adult who is not happy with her life. Ruth eventually gives up on all of her hopes and dreams and tries to help Kathy and Tommy have a better life.

Ruth is Kathy’s close childhood friend. Kathy lives with Ruth at Hailsham and at the Cottages, and later becomes Ruth’s carer when Ruth is a donor. At Hailsham, Ruth is outspoken and hot-tempered. She is a natural leader among her friends, although she is often highly controlling as well. Ruth is a foil to Kathy’s quieter and more guarded personality, and the two argue frequently. But like Kathy, Ruth generally quarrels using subtle hints and indirection rather than direct confrontation. As a teenager, Ruth also begins a longstanding romantic relationship with Tommy. This is an underlying and unspoken source of tension in her friendship with Kathy, who has romantic feelings for Tommy as well.

At Hailsham, Ruth often leads her friends in make-believe games. Her most elaborate invention is the “secret guard,” dedicated to protecting her favorite guardian Miss Geraldine from an imaginary plot. The fantasy of the secret guard shows Ruth’s controlling personality, but it also reflects her larger tendency to “pretend” around her peers. Ruth often implies that she has special knowledge and privileges unavailable to other students. For instance, Ruth hints that she receives special favors from Miss Geraldine. This habit annoys Kathy, who usually suspects that Ruth is lying and quarrels with her over it. However, Ruth’s pretending also shows her earnest desire to believe in hopeful possibilities. At Hailsham, her hints about Miss Geraldine reflect her longing for affection from a caring adult. At the Cottages, Ruth indulges in the fantasy of her “dream future” and pins her hopes on the vague story of her “possible,” or a person who resembles her and from whose DNA she may have been cloned, in Norfolk.

Ruth can be capricious and unkind to both Tommy and Kathy. In her attempts to fit in at the Cottages, she often ignores and mocks both of them. However, Ruth has the capacity for deep generosity and thoughtfulness as well. When Kathy loses her Judy Bridgewater tape at Hailsham, for instance, Ruth marshals their classmates to search for it and then gifts her a different tape as a substitute. Later, Ruth also offers Kathy and Tommy the gift of Madame’s address, which demonstrates Ruth’s inherent hopefulness because she believes Kathy and Tommy still have the chance to ask Madame for a deferral on their donations. Through the offering of Madame’s address, Ruth shows her sincere desire to make amends for keeping Kathy and Tommy apart.