The protests coincide with "National Day of Action for Education." Rallies, marches, teach-ins and walkouts are planned at about 30 campuses statewide.
The protesters are calling on Gov. Jerry Brown to reject any budget deal that includes education cuts or tuition hikes. They're also pushing for a tax increase on millionaires to help fund education.
The campus protests are a prelude to a major "Occupy the Capitol march and rally in Sacramento on Monday.
The Associated Press contributed to this report.