This article provides an analysis of teachers' perceptions of and responses to gendered harassment in Canadian secondary schools based on in-depth interviews with six teachers in one urban school district. Gendered harassment includes any behaviour that polices and reinforces traditional heterosexual gender norms such as (hetero)sexual harassment, homophobic harassment, and harassment for gender non-conformity. This study shows that educators experience a combination of external and internal influences that act as either "barriers" or "motivators" for intervention. Some of the external barriers include: lack of institutional support from administrators; lack of formal education on the issue; inconsistent response from colleagues; fear of parent backlash; and negative community response. By gaining a better understanding of the complex factors that shape how teachers view and respond to gendered harassment, we can work towards more effective solutions to reduce these behaviours in schools. (Contains 2 figures, 1 table and 1 note.)