The proposal was shot down last year by school boards and teachers.
Supporters said later start times improve health and help offset sleep deprivation in teens.
MORE: Colorado school district switches to 4-day week
The measure passed narrowly in both chambers following a debate that did not adhere to party lines.
"This is the single most cost-effective thing we can do to improve high school graduation rates," Assemblyman Jay Obernolte, R-Hesperia, said.
If Gov. Jerry Brown signs the bill, schools will have about three years to comply.
Currently, more than 80 percent of schools start before 8:30 a.m. Rural schools would be exempt from the mandate.
The Associated Press contributed to this report.