Background: There is growing interest in school-based interventions for building resilience in children facing trauma and adversity. Recent studies focus on teacher training as an effective way to enhance resilience in their students, and emphasize the need for additional evidence-based practice. Objective: The aim of this study was to evaluate the effectiveness of a short-term resilience-building teacher intervention on reducing post-traumatic distress in students in the context of exposure to recurrent rocket attacks in Israel. Methods: A quasi-experimental, cluster randomized design employing intervention and wait-list control groups was implemented with students from grades four-six (N = 563) in four schools in Acre in the aftermath of the Second Lebanon War. We assessed the students' trauma exposure, posttraumatic symptoms and anxiety before and after the intervention or the wait-list condition. Results: There was a significantly (p < 0.001) greater decrease of posttraumatic symptoms and anxiety levels among the students whose teachers participated in the intervention group as compared to students whose teachers were in the wait-list control group. A multiple regression model showed that this greater decrease in posttraumatic symptoms and anxiety levels was statistically significant after controlling for demographic variables, trauma exposure and past trauma history. Conclusion: The results of this study show that the training of teachers alone in building resilience can effectively lower post-traumatic distress and anxiety in their students. The empowerment of teachers and by building upon their expertise and experience are crucial for creating sustainability in school-based interventions.