Teacher work engagement is essential for schools to achieve their educational objectives and student learning outcomes. Among all the influencing factors, supportive workplace resources from diverse sources such as distributed leadership, trust, and self-efficacy have been cited as important factors affecting teachers' engagement in their work. Conservation of resources theory proposes a theoretical mechanism of how supportive resources can facilitate employee engagement; this study aims to further examine and investigate the ways in which teacher work engagement is enhanced by distributed leadership and the role of teacher efficacy and trust in this relationship. The findings of a survey involving 577 Chinese primary school teachers reveal that teacher efficacy completely mediates the positive relationship between distributed leadership and teacher work engagement. Distributed leadership also leads to increased teacher efficacy owing to higher levels of trust. These results suggest that distributed leadership is a highly effective approach that school administrators can adopt and that a workplace climate with a high level of interpersonal trust should be considered to further improve the effectiveness of school leadership and management.