This study aims to explore teacher professional learning in Turkey by investigating the effects of principal leadership and teacher trust on teacher professional learning, controlling for important school and teacher characteristics. Using teacher and principal survey data collected from 85 elementary and secondary Turkish schools across the country in 2018-2019 academic year, the study employs hierarchical linear modelling to investigate whether and to what extent principals' learning-centred leadership and teacher trust predict teachers' participation in professional learning. The results show, first, that only a small proportion of variation in teacher professional learning can be attributed to between-school factors. Second, principals' learning-centred leadership is not associated with teacher learning, and individual and school level trust among teachers provides a better explanation of the largest variation in teacher professional learning. Finally, elementary schools differ significantly from high schools in terms of teachers' involvement in teacher professional learning. Relevant implications for policymakers, practitioners, and researchers are discussed.