This qualitative study examines the concept of teacher leadership from the perspective of those who practice it. Viewed through the lens of identity theory, analysis yielded five categories that define and describe a teacher leader--namely, as a decision maker, an educational role model, a positional designee, a supra-practitioner, and a visionary. Findings reveal that the social structure where leadership is practiced shapes the definition of teacher leadership. Role identification within the social structure can assist principals in developing a healthy work climate that promotes distributed leadership. (Contains 3 tables and 1 note.)