The bus driver was also hurt in the accident. It happened Friday morning near far west suburban Big Rock.
Everyone on the bus was treated and released from the hospital.
Authorities are looking into whether the bus driver may have fallen asleep at the wheel.
It happened as the bus was on Granart Road near Camp Dean Road in Big Rock Township.
Holly Vantilburg was one of the students on board. She described the dramatic scene.
"I woke up to my bus attendant yelling at bus driver, 'The bus is tipping over,' or 'Watch what you're doing. Are you awake?' " said Vantilburg.
Police confirm, the driver veered off the road, and the bus landed in a ditch and rolled onto its side.
Vantilburg says the bus driver has fallen asleep behind the wheel many times before. She, along with her mother Barbara, have even tried to reach out for help.
"People who are driving behind him have called in and said, 'Hey, this guy's swerving,' and yet the bus company has done nothing," said Vantilburg.
"The district called me to say there had been an accident, and I said, if it's the driver that I've called in on twice already who was falling asleep...sure enough, it was," said Barbara Vantilburg.
Nine students were on the bus, six of them special needs students, all on their way to Krejci Academy and The Mansion High School in Naperville, a school that treats students for emotional, behavioral and developmental issues. The school is not in charge of hiring the bus company. Fifty different districts that bus in their kids share the expense.
The bus is owned by Illinois Central Bus Company.
Authorities say almost everyone was buckled in. They said many witnesses quickly jumped in to help, preventing the crash from being far more serious.
Kane County authorities are investigating the crash. They are looking into the possibility that the driver may have fallen asleep behind the wheel.
Telephone calls to Illinois Central Bus Company for comment were not returned by late Friday afternoon.