Civility is an important construct to be addressed in relation to child and youth development. The issue of classroom incivility is of particular interest, given its potential negative impacts to both the psychosocial well-being of adolescents and the overall learning environment. Therefore, the current study sought to investigate similarities and differences between perceptions of middle and high school students and teachers. Participants consisted of 40 intermediate and high school teachers and 52 students in Grades 7-12. Both students and teachers rated uncivil behaviour in the classroom based on how serious they thought it was and how often it occurred in their classroom. Further, participants responded to open-ended questions to allow for a deeper exploration of the viewpoints and lived experiences of both students and teachers. Findings suggest that adolescent students consider uncivil behaviours that may be seen as disrespectful towards the teacher as more uncivil than do teachers themselves. Teachers tended to focus on adolescents engaging in uncivil behaviuor towards each other as being more serious as well as a focus the negative implications of classroom incivility to the learning environment. These differing perceptions of uncivil behaviour in the classroom have important implications for intervention within educational settings.