The study examines how the toxic leadership behaviors of school principals relate to teachers' perceived stress. It is a correlational survey model, and the sample consists of 278 primary and secondary school teachers. We collected the data with the Perceived Stress Scale and Toxic Leadership Scale. The findings show that gender does not cause a statistical difference in perceived stress and all dimensions of toxic leadership. The stress levels of branch teachers are higher than those of primary school teachers, with a statistically significant difference. The perception of branch teachers in terms of ignorance, self-interest, and a negative mental state of toxic leadership is significantly higher than that of classroom teachers. A moderately significant positive relationship exists between teachers' perceptions of stress and all dimensions of toxic leadership. 20% of teachers' perceptions of stress are explained by toxic leadership. The negative mental state of school principals is a significant predictor of teachers' perceptions of stress.