Lindenhurst police said the crash happened around 11:30 p.m. in the 1700-block of Grand Avenue.
Investigators said a vehicle traveling eastbound on Grand Avenue left the roadway and struck a tree.
Responding officers found the car engulfed in flames with four people trapped inside, police said. The Lake Villa Fire Protection District extinguished the fire.
Two Zion boys, 11 and 16 years old, were pronounced dead at the scene, police said.
Two 20-year-old men, one from Zion and another from Beach Park, were hospitalized in critical condition.
The Lindenhurst Police Department and the Lake County Major Crash Assistance Team are investigating.