Nearly 12,000 students will be out of class in Newton on Friday after city teachers voted to go on strike.

Newton Teacher Association President Michael Zilles made the announcement Thursday evening in front of City Hall that 98% of the union voted to authorize the strike to begin Friday, as teachers have gone without contract since the beginning of the school year.

The previous contract expired Aug. 31, and Mayor Ruthanne Fuller along with the City Council and School Committee had pressed the teachers union not to go on strike. Newton is the ninth largest school district in the state.

“The membership of the Newton Teachers Association is standing up for the citizens, the students and the educators of Newton,” Zilles said, “and we are saying ‘Mayor Fuller, enough is enough.’”

City voters turned down a $9.2 million property tax increase that would have supported city services and schools last March. Teachers have held various rallies urging the mayor to fund the schools properly and not to rely on voters approving a proposition 2 ½ to do so.

The teachers association in December voted no confidence in Fuller and the School Committee.

In a Wednesday letter, union leaders highlighted how they felt “deeply disturbed” that they did  “not see any meaningful movement on the part of Mayor Fuller and the School Committee to come to a fair agreement with us.”

“Newton has more than enough money available to fund a living wage for aides and behavior therapists, offer classroom teachers competitive pay raises, hire more social workers and support staff to address the student mental health crisis, and to establish modern, humane paid family leave for all educators,” leaders wrote.

School Committee members have filed a “strike petition” with the state Department of Labor Relations.

Under state law, it is illegal for public employees, including teachers, to go on strike.

Newton’s contract escalation follows similar teacher strikes in Andover, Woburn, Haverhill, Malden and Brookline, which accrued escalating fines for the unions.

Speaking to reporters after the union’s announcement Thursday evening, Fuller called it a “sad day” and blasted the decision to go on strike.

“Students are our number one priority,” she said. “The adults belong at the negotiating table. The students belong in the classroom. The NTA should not be putting kids in the middle.”