This study investigates how and under what conditions distributed leadership influences teachers’ organisational citizenship behaviours. Using survey data from a sample of 419 teachers working in primary and secondary schools across six provinces in Türkiye, the current study tested a moderation model of distributed leadership’s impacts on teachers’ organisational citizenship behaviours, with trust in principal as the moderator. A regression-based moderation analysis was performed to examine the relationships between the study variables. The results demonstrated that distributed leadership is significantly associated with organisational citizenship behaviours, and trust in principal significantly moderates this link. Furthermore, distributed leadership fails to exert a significant influence on organisational citizenship behaviours when trust in principal is relatively low, indicating the pivotal role of trust as a relational context factor in elucidating the leadership’s impact on organisational citizenship behaviours. The results contribute to a deeper understanding of how the relational aspects of the workplace influence the impact of distributed leadership practices on positive teacher behaviours. The study has several implications for theory, policy and practice.