Voters approved Measure A, a $589 annual school parcel tax, by 79.36 percent, far more than the two-thirds needed.
The approval percentage was the highest ever for a parcel tax in Palo Alto, according to campaign consultant Charles Heath of San Francisco-based TBWB Strategies.
The result is "really energizing," Palo Alto Superintendent Kevin Skelly said. "This is a big 'yes' to our children and our community."
More than 50 percent of registered voters in the school district cast ballots in the mail-only campaign.
The tax replaces the current $493-per-parcel-per-year tax. It is expected to generate an annual $11.2 million, about 7 percent of the operating budget of the Palo Alto Unified School District.
The tax carries a 2 percent annual escalation adjustment and an optional exemption for people over age 65. It will expire in six years.
"This is incredibly important for our school district," Board of Education President Barbara Klausner told campaign volunteers at a victory celebration Tuesday night at the home of Sunny and Dan Dykwel.
"This is a new reality for California and for our schools. ... This is what we need to do to protect our schools."
School parcel taxes also passed Tuesday in the Menlo Park and Portola Valley school districts, as well as in Sunnyvale's Fremont Union High School District, San Jose's Union Elementary School District and the Loma Prieta Joint Union Elementary School District.
Measure A campaign Co-Chair Tracy Stevens said more than 500 people had volunteered in 35 phone-bank sessions during the campaign, calling 25,000 voters.
"We did call several people repeatedly and they let us know that," Stevens said to laughter from fellow volunteers. Repeat calls were made to people who hadn't yet sent in their mail-in ballots or whose ballots hadn't yet been listed as received.
"I'm not a big fan of phone banks. … I do not like getting the calls. But they work."
Heath said Palo Alto's 79.36 percent approval is "in the stratosphere" for school parcel-tax results, although other communities occasionally have reached approval ratings of more than 80 percent.
"It's a strong mandate and a high turnout," Heath said, noting the 50 percent-plus turnout refutes criticism that mail-in ballots squelch participation.
"It's also notable that this occurred in a down economy."