Chopper 7 was over the scene on northbound Interstate 294 just before 7:30 a.m.
Video shows smoke billowing from the semi-trailer at La Grange Road, near Western Springs.
Firefighters have since extinguished the flames. At least two righthand lanes were closed for some time as traffic got by slowly.
Whether anyone was injured in the fire was not immediately clear, but an ambulance could be seen on standby.
Further information was not immediately available.