Leaders’ role is significant in motivating employee performance. The present study examines the influence of transformational leadership and public service motivation (PSM) on task performance of nurses in three southernmost provinces in Thailand. Based on the data collected from 813 nurses in public hospitals, the results showed that the proposed model was well-fitted to the empirical data. The results of the study indicated that transformational leadership and public service motivation had effects directly on both task performance and contextual performance. Furthermore, transformational leadership had indirect effects on task performance and contextual performance through public service motivation. These findings suggest that nurses’ job performance could be enhanced by the motivational influence of their immediate leaders.