This study focused on evaluating the psychometric properties of the Negative Acts Questionnaire-Revised (NAQ-R) within a sample of Brazilian teachers, addressing the gap in the scientific literature on workplace bullying in Brazil. Despite over 52,000 recorded cases in 2021, most research on school violence in Brazil has overlooked teacher victimization, focusing instead on students. The NAQ-R, developed to measure exposure to workplace bullying, originally included 23 items but was later revised to 22. It assesses three factors of bullying: personal, work-related, and physically intimidating forms. However, this study discovered a two-factor structure, combining personal bullying with physically intimidating forms. Using a large sample of Brazilian teachers, exploratory and confirmatory factor analyses were performed, alongside assessing convergent validity with the Self-Reporting Questionnaire-20 (SRQ-20), an instrument for screening common mental disorders. The NAQ-R exhibited adequate internal consistency and validity, correlating positively with the SRQ-20, indicating its effectiveness in measuring workplace bullying among teachers. The study, however, had limitations. Data collection via convenience sampling might have influenced the results. Despite this, the findings align with international studies, suggesting the measure’s stability. The study highlights the need for further qualitative research to deepen our understanding of workplace bullying. Interventions informed by the detection of workplace bullying could include organizational policies against work harassment and the adoption of ethical leadership styles.