Background: Authentic leadership has been consistently cited as a strong precursor of sustained job performance and work effectiveness in nurses; however, studies linking authentic leadership with nurses' safety actions, nurse-assessed adverse patient events and nursing care quality are scarce. Aim: To examine whether nurses' safety actions mediate the relationship between authentic leadership, nurse-assessed adverse events and nursing care quality. Methods: A multi-centre, cross-sectional study involving 1,608 nurses employed in acute care facilities in Oman. Multi-stage regression analysis was conducted in testing for the mediation model. Findings: Nurse managers in Oman were perceived to be highly authentic by their staff nurses. Authentic leadership significantly predicted nurses' safety actions (β = 0.168, p <.001), decrease in nurse-assessed adverse events (β = −0.017, p =.024) and increase in care quality (β = 0.121, p <.001). Further, the association between authentic leadership and nurse-assessed adverse events (β = −0.063, p =.057) and care quality (β = 0.038, p =.002) was mediated by nurses' safety actions. Conclusion: Results suggest the importance of developing nurse managers' authentic leadership to foster nurses' safety actions and reduce adverse patient outcomes and promote nursing care quality. Implications for nursing management: Organizational efforts to address patient safety issues should be directed towards developing authentic leadership in nurse managers through leadership programmes, periodic evaluation of leadership competencies (e.g., 360-degree or a bottom-up performance evaluation), and a creation of a safe culture in which nurses can openly report safety concerns for corrective action.