This study used questionnaires and systematic behavioural observations to examine how teachers, students and external observers perceived classroom disruptions, the teacher-student relationship and classroom management in grade 5 and 6 classrooms in Switzerland. The questionnaire showed that the students of a class agreed to a certain extent in their ratings of classroom disruptions, the teacher-student relationship and classroom management. Comparison of teachers' and students' ratings showed that agreement on these constructs varied. We found weak to moderate agreement on classroom disruptions, a weak correspondence for the teacher-student relationship, and no association on classroom management. The results of the behavioural observation showed a moderate agreement between external observers' and students' ratings, but no association between external observers' and class teachers' ratings and only a weak correspondence with the subject teacher ratings. Thus external observers' low-inference observations corresponded far better with students' than teachers' ratings. To sum up, students, teachers and observers perceive classroom processes differently.