The Ontario Liberals are promising to spend $10 billion to build and repair schools if elected in June.
Liberal Leader Steven Del Duca says it would be funded by cancelling the planned Highway 413 around the Greater Toronto Area.
The Progressive Conservatives have not provided an overall cost estimate for the project, but the Liberals oppose it, saying it will destroy farmland and won't save commuters much time.
The Liberals say their capital schools plan would build 200 more schools, and repair, upgrade and rebuild another 4,500.
They say the renovations would also include new ventilation systems in every school.
The school repair backlog has been pegged in recent years around $16 billion.