Anastasia Elizabeth "Stacey" McGill is the treasurer of The Babysitter's Club. Stacey is in charge of the manila envelope that holds the club's money. She collects dues and keeps track of how much money everyone makes and records it in her section of The Record Book. She is thirteen years old and is in the eighth grade at Stoneybrook Middle School.Stacey's parents are Edward McGill and Maureen McGill. Stacey has no brothers or sisters.
Stacey and her family first moved to Stoneybrook the summer before seventh grade. Previously, she had lived her whole life in New York City. She and her family moved so that Stacey could get a fresh start after being diagnosed with Type 1 diabetes therefore missing a lot of school and falling out with her friends (including best friend Laine Cummings) in the process.