The Illinois Senate is expected to take up a school funding overhaul that will increase aid to all of the state's more than 800 districts.
Lawmakers are set to convene Tuesday to vote on the measure, which the Illinois House approved late Monday. Republican Gov. Bruce Rauner has said he'll sign the bill.
Supporters have called the legislation "historic" because it will reduce huge disparities in per-student funding between districts. The measure also provides $75 million for tax credits for people who contributed to private school scholarships.
Teacher unions opposed the credits, saying taxpayer money shouldn't be used toward private schools.
But even some legislators who initially opposed the measure changed to "yes" votes late Monday. They feared that without another funding plan available, schools would run out of money.