The crash happened early Saturday in northwest suburban Prospect Heights.
The Cook County Medical Examiner says all three teens died of multiple injuries caused when the car struck a fixed object. The medical examiner has identified one of the victims as 16-year old Freddy Najera of Mount Prospect. Names of the other two have not been released. A fourth teen survived the crash.
Toxicology tests will be done to determine if drugs or alcohol were involved. Police say the car was going at a high rate of speed when it crashed.