Eight out of 10 secondary teachers feel indiscipline in schools is a major problem, according to the Scottish Secondary Teachers' Association (SSTA).
Teachers said indiscipline was increasing
A survey of SSTA members was revealed at the union's annual congress in Aviemore.
According to the SSTA's survey of 2,500 teachers, 77% of its members think the problem of indiscipline is now "significant" to "extremely significant".
And half of all teachers asked thought the problem had increased greatly in the past two years.
Right to respect
Teachers said that changing pupil attitudes was the main cause of disruption and violence in schools, and lack of parental support also plays a major part in the problem.
The SSTA said it is clear that the problem of indiscipline is here and it is not going away.
The union is launching a poster stating teachers' rights to work without fear of any form of intimidation.
It wants the poster promoting dignity at work to be displayed in every school to remind staff, pupils and visitors that teachers have a right to be respected.