The union also said no strike date has been decided, but if they don't get what they want from the district they could go on strike by the end of the month.
Both sides are waiting on a fact-finding report-- results of that report will be available in 10 days.
RELATED: Oakland teachers hold rally, walkout over contract talks
The vote took place at Oakland Tech High School Monday.
On Friday, students walked out of class at Oakland Tech to show solidarity with the teachers, saying their teachers should be able to afford to live in the Bay Area.
BUILDING A BETTER BAY AREA: Keeping teachers in the Bay Area
Teachers have been working without a contract since July 2017. They are fighting for smaller class sizes and higher salaries.
Oakland teachers want a 12 percent raise over three years. The school district is offering five percent. The district is facing a $30 million deficit. The school board says it will have to close some schools.
Take a look at the latest stories and videos about the Oakland teacher strike.