Teachers in Gateshead are to go on strike in a dispute over the way misbehaving pupils are dealt with.
Members of the NASUWT union said there was a “history of issues” at Heworth Grange School.
About 40 teachers at the school will start the first of six planned days of strike action on Thursday.
Headteacher Chris Richardson said new systems have been put in place to tackle the issues, and the school would remain open for Year 11 and sixth form.
NASUWT regional organiser Simon Kennedy said the issue revolved around the way pupils who are ordered to leave lessons for misbehaving are then dealt with.
He said too often the pupil is sent back into the lesson without appropriate action being taken.
“This undermines the teachers and affects every other child in the classroom,” Mr Kennedy said.
“Children are challenging in every school, we are not saying they are worse at Heworth Grange, but where there are issues we say the trust is not dealing with them.”
Mr Kennedy said the other strike days were planned for March but he hoped the issues will have been resolved before then.
Mr Richardson said he was “saddened” and “disappointed” but there was a “strong desire to continue to have dialogue with staff and unions”.
The headteacher said a new behaviour policy had been implemented, adding: “While we are pleased with the progress that is being made, it will take time to embed.”
Heworth Grange was taken over by the Consilium Academies Trust in February 2018 and has space for about 1,300 pupils aged between 11 and 18.