More than 100 people, mostly teachers, demonstrated against Education Secretary Betsy DeVos in San Francisco on Tuesday.
The demonstrators walked from the federal building to the San Francisco Unified School District headquarters to deliver their message.
A spokeswoman for United Educators of San Francisco said low pay is already driving teachers out of the city, and DeVos's policies toward privatization will further erode teacher pay and education funding.
"Betsy DeVos is a billionaire who does not believe in public education," said Lita Blanc. "She's in the process of trying to dismantle education."
The union and the school district are currently involved in contract negotiations over pay and benefits. Union members say the city could lose hundreds of teachers in the coming years due to the cost of living if pay is not increased.