EN
The teacher’s misbehaviour has an adverse influence on students’ motivation and adjustment in school. It even has more permanent effects on students than the teacher’s good behaviour. The objective of this study was to apply Korthagen’s model of levels of change in exploring teachers’ most unacceptable characteristics from the perspective of students (n = 158), teachers (n = 78) and parents (n = 148), and to reveal possible differences depending on primary and secondary school and the length of teachers’ experience. The listed characteristics fit Korthagen’s model mostly in the levels of mission, behaviour and identity. Some differences were found between primary and secondary school, as well as ones related to teachers’ length of experience.