This paper asks how complexity theory informs the role of leadership in organizations. Complexity theory is a science of complexly interacting systems; it explores the nature of interaction and adaptation in such systems and how they influence such things as emergence, innovation, and fitness. We argue that complexity theory focuses leadership efforts on behaviors that enable organizational effectiveness, as opposed to determining or guiding effectiveness. Complexity science broadens conceptualizations of leadership from perspectives that are heavily invested in psychology (e.g., human relations models) to include processes for managing dynamic systems an interconnectivity. We develop a definition of organizational complexity and apply it to leadership science, discuss strategies for enabling complexity theory and other currently important leadership theories. The paper concludes with a discussion of possible implications for research strategies in the social sciences.