The Independent School League (ISL) is an athletic conference comprising 9 private secondary schools in the Chicago metro area.
The schools are all relatively small, most belonging to the smaller classes of competition offered by the IHSA.
[10] The league initially comprised eight teams: Chicago Lab, Elgin, Latin, Morgan Park, North Shore, Francis W. Parker, Harvard-St. George, and Glenwood.
Lake Forest Academy left the ISL in 2008 and rejoined in 2021.
[11] Regina Dominican High School joined in 2022.