This study examines the impact of teachers' verbal aggressiveness on high school students’ academic performance, emotional well-being, and classroom engagement, addressing a critical gap in understanding how negative teacher behavior impacts students. Using a quantitative correlational design, data were collected through a 20-item Likert scale questionnaire completed by 70 high school students from diverse academic streams. The findings reveal that verbal aggression by teachers has significant adverse effects, with students reporting decreased motivation, academic disengagement, and negative emotional impacts such as anxiety and low self-esteem. Public humiliation emerged as particularly damaging, leading to feelings of resentment and vulnerability to bullying. Conversely, positive teacher behaviors, such as praise and encouragement, were strongly associated with improved classroom participation, enhanced motivation, and better academic outcomes. The study highlights the urgent need for professional development programs that equip teachers with effective communication skills and awareness of the psychological impact of their behaviors. Creating a respectful and supportive classroom atmosphere can mitigate the harmful effects of verbal aggression, fostering student engagement, emotional resilience, and academic success.