Teaching union NASUWT launched the hotline a week ago amid concerns about the treatment of staff.
Around 50 teachers have contacted the hotline to report feeling intimidated, belittled and harassed in the workplace, with many complaining of little support being given to them, particularly when they report incidents of pupil indiscipline.
The union has already announced plans for members at Rosshall Academy to strike next Tuesday and Wednesday over claims of bullying and intimidation, while staff at All Saints Secondary are being balloted over industrial action.
Glasgow City Council said the planned strike is "deeply regrettable" and that it has tried to reach a resolution.
Chris Keates, acting general secretary of NASUWT, said: "We opened the hotline in response to concerns raised by members in Glasgow over the abuse of their contractual rights over cover and reports of intimidating and bullying behaviour towards staff.
"The response so far from teachers shows that our concerns were well founded and the hotline has exposed a number of serious issues, in particular the lack of support for teachers in managing pupil behaviour and the lack of respect for them as skilled professionals.
"Teachers should not face threats and intimidation when they are simply trying to stand up for their basic workplace rights and when they are trying to maintain good order and high standards of pupil behaviour.
"Given the response to the hotline we will keep it open for a while longer. The hotline has also given many teachers the confidence to come forward and raise their concerns and also to know that their concerns are shared by others."
The NASUWT hotline opened on September 27 and is for any teacher in Glasgow to report, by text or voicemail, any incidents they have experienced or witnessed.
They can contact it anonymously and those who need help and support will be directed towards it.
Calls to the hotline included one person who said: "When I approached my principal teacher and raised concerns that I was stressed and anxious (I ended up being treated for this long-term including counselling and medication), I was informed that 'your mental health isn't my problem'. They then denied ever having made this comment."
Jane Peckham, NASUWT's national official in Scotland, said: "The response so far from members to the hotline indicates the deep level of frustration and anger of teachers in Glasgow over how they are being treated."
A Glasgow City Council spokeswoman said: "It's deeply regrettable that the NASUWT union has not called off the planned strike action at Rosshall Academy next week despite the council's best efforts to try and reach a resolution.
"In fact, the union has declined to either sit around the negotiating table or respond to numerous communications - including an offer to not process deductions for those teachers who have not attended agreed activities which take place out-with the pupil day.
"This is what we understand to be the main point of the dispute and are therefore puzzled as to why the union is determined to continue with their planned action that will obviously result in a two-day disruption to the pupils' education at the school.
"We would urge senior officers of NASUWT to accept our offer to talk and reach a satisfactory conclusion for their members that will not impact our families as they have advised us of more action in other schools across the city."