The purpose of the study was to further examine the potential efficacy of the Bully Prevention in Positive Behavior Support (BP-PBS) program in addressing bullying in an urban public elementary school with a large and diverse student population, implementing school-wide positive behavior support with relatively low fidelity. Specifically, the study examined the extent to which BP-PBS could decrease target students’ bullying behavior across settings and increase appropriate active response to bullying of students being bullied. Changes in the students’ perceptions and attitudes on school safety were also examined. This study involved a multiple probe design across participants targeting multiple settings for six students (three bullies and three victims) to assess the impact of the BP-PBS intervention and to examine its generalization effects to a non-targeted setting. The results indicated that the BP-PBS intervention was effective in reducing the target students’ bullying maintained by peer and adult attention and increasing active response to bullying. The intervention also increased positive perceptions and attitudes on school safety in students being bullied and the bullies. Changes in student bullying and appropriate and inappropriate responses to bullying were generalized to non-training settings and remained at intervention levels for all participants. Social validity surveys indicated high acceptability of the BP-PBS intervention by teachers.