Munger's Proposition 38 would generate about $10 billion annually for schools by taxing all but the poorest Californians.
The Governor's tax initiative, Proposition 30, raises about $6 billion a year primarily by taxing the wealthy.
If Brown's fails, it would trigger more than $5 billion in cuts to schools and community colleges.
In an interview with Capital Public Radio, Munger called Brown's emphasis on those cuts a political move designed to scare people.
MUNGER: "The Governor's tax measure doesn't actually contain new money for schools, oh a tiny amount. I think it doesn't even deserve the description of bandaid because it's just so small it isn't even that."
Munger has personally donated $28 million to the Yes on 38 Campaign - including $8 million just last week.