In this study, the effect of school principals' administrative mentality on teachers' participation in the decision-making process was analysed via the intermediary role of teachers' trust in principals. In this study, which utilised structural equation modelling (SEM) to analyse conceptual relationships, the sample consisted of 646 teachers who worked in various school types in the Cekmekoy district of Istanbul. In the findings, a positive correlation was found between benevolent and moral leadership (dimensions of paternalistic leadership behaviour), and trust in principals and teachers' participation in decision making. On the other hand, a negative and significant relationship was found between the authoritarian leadership dimension and trust in principals and teachers' participation. The results of the SEM analysis, in which the conceptual model was tested, indicated that the benevolent and moral leadership dimensions of paternalistic leadership could positively predict trust in the administrator and teachers' participation in decision making. As for authoritarian leadership, it negatively predicted teachers' participation in decision making, and trust in principals played a full intermediary role in this relationship. When these findings were synthesised, morality and benevolence were found to affect teachers' trust in principals and participation positively, while authoritarian leadership was found to have a negative effect.