Professional learning communities are essential for school success, and principal leadership is crucial for teachers' participation in them. Based on social exchange theory and ambidextrous leadership theory, this study explored the mediating role of teachers' trust in principals between moral leadership and professional learning communities and the moderating role of principals' controlling behavior in this relationship. A total of 577 elementary school teachers in China participated in this study. The study found that moral leadership was positively related to professional learning communities, and this relationship was mediated by teachers' trust in principals. Additionally, principals' controlling behavior positively moderated the relationship between moral leadership and trust in principals, and negatively moderated the relationship between moral leadership and professional learning communities. These results contribute to the delivery of guidance for principals to enhance teacher trust and develop professional learning communities.