Staff at Bannerman High School in Baillieston, a suburb of Glasgow, are considering a walkout if pupil behaviour shows no sign of improving.
They have been taking action short of strike since October, claiming there has been a lack of action by Glasgow City Council to tackle persistent violence towards staff.
The NASUWT union, which represents 32 teachers at the school, says six violent incidents have been recorded since pupils returned after the Easter break last month.
Staff claim behaviour management policies are not being followed by senior management, and say they feel there are few consequences for pupils who are persistently disruptive.
Patrick Roach, NASUWT general secretary, said: “Members at Bannerman are increasingly worried for their personal safety and angry at the failure of their employer and Glasgow City Council to fulfil their duty to protect them and the majority of well-behaved pupils from violence and disruption.”
According to figures obtained by NASUWT, 20 serious incidents of violence and aggression at the school were logged on the council’s health and safety management system during the last academic year.
In 2019/20, 41 incidents were recorded on the council’s system.
Dr Roach added: “The attitude appears to be one of blaming teachers for poor behaviour, rather than holding pupils accountable, and this is being aided and abetted by the misuse and abuse of restorative behaviour conversations, which members feel have become synonymous with no punishment or sanctions for unacceptable behaviour.
“We have given the employer every opportunity to address these issues. All our members want is to be able to get on with their jobs free from the threat of violence and abuse at work.”
A Glasgow City Council spokeswoman said: “We do not condone abuse of any sort – either verbal or physical – that is directed towards our teachers or school staff and who deserve to feel respected and safe in their work place.
“Any reported incidents are dealt with quickly and effectively and a resolution agreed.”