The authors examined whether safety-specific trust moderates or mediates the relationship between safety-specific transformational leadership and subordinates' safety citizenship behavior. Data from 139 subordinate-supervisor dyads were collected from the United Kingdom construction industry and analyzed using hierarchical regression models. Results showed that safety-specific trust moderated rather than mediated the effects of safety-specific transformational leaders on subordinates' behavior. Specifically, in conditions of high and moderate safety-specific trust, leaders had a significant effect on subordinates' safety citizenship behavior. However, in conditions of low safety-specific trust, leaders did not significantly influence subordinates' safety citizenship behavior. The implications of these findings for general safety theory and practice are discussed.