AbstractDespite the expanding body of research on school bullying and interventions, knowledge of what makes teachers intervene in bullying situations remains limited. Based on the Theory of Planned Behavior, a theoretical framework that combined the predictive elements contributing to teachers’ likelihood of intervening was tested empirically. The model used teachers’ characteristics and behavior as predictors of their tendencies to identify, prevent, and reduce bullying. Survey data of 114 primary school teachers (Mage = 42 years, 87% female, 10 schools) and 66 secondary school teachers (Mage = 40 years, 44% female, 5 schools) were analyzed using multilevel regression models. Teachers’ attitudes (including perceived seriousness of bullying) and behavioral control (including attribution styles) were related to teachers’ likelihood of intervening in six hypothetical bullying situations. Two other main elements of the Theory of Planned Behavior (subjective norms, as measured with perceived collegial support) and the additional element of knowledge (about the distinguishing characteristics of bullying) were unrelated to the likelihood of intervention. These findings emphasize the importance of teachers’ attitudes and attribution styles to the likelihood of intervention. These can be emphasized in teacher training and anti-bullying programs to empower teachers more systematically.