Problems of work stress and thermal comfort (PMV) affect teacher performance at Bina Wirawan Catholic Junior High School, Maumere, Sikka Regency, and the role of emotional intelligence in mediating the relationship. This is important to understand to improve teacher performance through stress management, environmental comfort, and strengthening emotional intelligence. This study uses a quantitative method. The saturated sample is 28 (twenty-eight) teachers at Yapenthom 1 Catholic Junior High School, Maumere. Primary and secondary data sources. The data collection technique used was conducting a field study with interviews, installing measuring instruments to determine thermal comfort in schools, and distributing questionnaires to teachers. The results of the study showed that 1). Work Stress and Teacher Performance have a significant influence on teacher performance. Stress can interfere with concentration, interpersonal relationships, and reduce work motivation, which ultimately has a negative impact on teacher performance. 2) Thermal Comfort and Teacher Performance do not show a significant direct influence on teacher performance. However, thermal comfort has been shown to have a positive influence on teacher emotional intelligence. 3). Thermal Comfort and Emotional Intelligence are that a comfortable environment can improve mood, reduce stress, and support the development of emotional intelligence. 4) Emotional Intelligence and Teacher Performance are proven to have a very significant influence on teacher performance. Teachers with high emotional intelligence are better able to build good relationships with students, create a positive learning atmosphere, and motivate students. 5) Thermal Comfort, Emotional Intelligence, and Teacher Performance is Thermal comfort affects teacher performance through emotional intelligence.