The pivotal responsibility of educating and nurturing students in any society is on the shoulders of teachers, whose knowledge, affection, and commitment exert a great influence over students' lives. Therefore, attending to teachers' emotional state and satisfaction with their profession is crucial. This study was therefore undertaken to investigate the relationship between Iranian English and nonEnglish teachers' job satisfaction and their teaching effectiveness. The relationship between these teachers' job satisfaction and their demographic background (e.g. teaching experience and gender) was also scrutinized. Using convenient sampling, 173 English and nonEnglish teachers were selected to participate in this research. In order to collect data, Kulsum (2000) Teacher Effectiveness Scale and Lester's (1987) Teacher Job Satisfaction questionnaire were used. The results revealed a positive correlation between teachers' job satisfaction and teaching effectiveness and this held true for both English and nonEnglish teachers. For policy makers and stakeholders in education, this study underlines the significance of addressing teachers' needs and their challenges to promote their job satisfaction.