Background: Violence and aggression in the classroom are often cited as a major concern within the teaching community. Teachers' perceptions of the appropriateness of intervention behaviours during aggressive incidents, however, are less often examined (Meyer, Astor, & Behre, 2002), nor how they compare to the perceptions of training teachers (John, 2002). Aims: This paper examines differences in the perceptions of practising and training teachers after exposure to an account of a violent incident where a school teacher is assaulted. The paper also investigates the relative and combined influence of classroom condition and teacher intervention on perceptions of classroom violence. Sample(s): Participants included 48 practising teachers, and 48 students undertaking a Postgraduate Certificate in Education (PGCE) also took part in the study. Methods. The study utilized a 2 ? 2 ? 2 between-subjects factorial design, manipulating the impact of classroom condition, teacher intervention, and observer status on evaluations of the teacher, assailant and school following an incident of violence against the teacher. Results. Classroom environment, teacher intervention, and observer status influenced evaluations of the teacher and school, but not the assailant. Conclusions: Implications of these findings and the applied importance of these results are discussed in relation to school policy, teacher training, and classroom maintenance.