We examined the positive impact of transformational leadership on IS success in organizations via two psychological mechanisms of system users' perceived organizational support and systems self-efficacy. Our conceptual model was assessed using a sample of 251 employees from a multi-national bank in Korea. Overall, our results supported the hypothesized relationships: transformational leadership was positively related to system users' IS success, and both perceived organizational support and systems self-efficacy of the system users mediated the relationship between transformational leadership and IS success. The results call for manager's attention to the importance of transformational leadership development in organizations.