Glenbrook South High School, or GBS, is a public four-year high school located in Glenview, Illinois, a north suburb of Chicago, in the United States. It is part of Northfield Township High School District, which also includes Glenbrook North High School. Glenbrook South should not be confused with Glenbard South High School, another suburban Chicago high school located in Glen Ellyn, Illinois that is also referred to as "GBS".