Mary Lila Grace first appears sitting down watching the volleyball game, She walks by Carrie and presumably saying something nasty. She then appears in Miss Collin's detention, standing next to Norma. Mary attended the prom with Dale Norbert, she was nominated for prom queen but lost to Carrie and Tommy Ross. When Carrie leaves the burning prom, she and Dale are running away from the flames. She presumably burned to death.
- Mary Lila Grace's name comes from Mary Lila Grace Thibodeau from the novel