My research focuses on the psychological processes of leadership that occur within and between small dynamic groups, such as teams or divisions, and larger social categories ranging from organizations to ethnic and national groups. More specifically, my research examines the social psychology of leadership and influence. I investigate the role of social identity processes in shaping group and organizational behavior, specifically leadership and followership. This research draws on and extends the social identity theory of leadership (Hogg, van Knippenberg, & Rast, 2012a, European Review of Social Psychology) and the theory of intergroup leadership (Hogg, van Knippenberg, & Rast, 2012b, Academy of Management Review) to examine the dynamic nature of leadership within and between groups. In my research, these theories are applied to real-world contexts such as political elections, organizational leadership, and intergroup conflicts.