In spite of a strong body of research examining teacher job satisfaction and teachers' assessment of their principals' behaviours, most studies focus on the educational systems in the first world countries. This quantitative study focuses on a lesser-examined educational context by comparing school teachers' job satisfaction levels and principals' instructional supervision behaviours in Turkish private and public schools. The results suggest that for all examined demographical characteristics of participating teachers (e.g., gender, school level, subject matter, and years of teaching); private school teachers had higher levels of job satisfaction and assessed their principals' instructional supervision behaviours higher than did public school teachers. These findings suggest there are more favourable working conditions in Turkish private schools than in public schools and support research trends on the topic of teacher job satisfaction from other countries.