Surrounded by children, the governor signed the bill during a ceremony at Wentworth Park.
The new law increases fines and encourages safety education for parents who do not put their kids in properly installed safety seats while driving.
"I believe in this law. I think everybody who has a child believes in the importance of taking care of our children in vehicles to make sure they're safe," said Quinn.
Illinois law requires any child under the age of eight who weighs less than 40 pounds to ride in a child safety seat.