Brown's proposal would backfill the state's general fund and guarantee funding to local governments for public safety. It would raise income taxes on a sliding scale on incomes over $250,000 a year for seven years and raise the state sales tax by a quarter cent for four years.
The rival proposal, backed by Los Angeles attorney Molly Munger, would raise income taxes on nearly all Californians on a sliding scale for 12 years, with the biggest increase on the wealthiest Californians.
Revenue from her proposal would go directly to public schools, while Brown's measure would use the money to prevent deeper cuts to schools and guarantee money for local public safety.
Associated Press writers Hannah Dreier and Don Thompson contributed to this story.