There is no shortage of research on the topic of organizational leadership, with hundreds of new empirical studies appearing annually. Most of this research has focused on the outcomes of leadership, and the possible effects of organizational leadership on employee commitment have not escaped attention. The goal of this chapter is to explain how various types of leadership influence different facets of employee commitment. To do so, the authors first investigate what is known about the influence of positive leadership on employee commitment. Secondly, they review the possible effects of negative forms of leadership on employee commitment. Thirdly, they explore the outcomes of high-quality leadership in alternative organizations, namely labor organizations. Lastly, they propose some research questions that will help to further understanding of the nature and effects of commitment.