One lasting legacy of the effective schools movement was the institutionalization of the term "instructional leadership" into the vocabulary of educational administration. Evidence from other recent reviews of the literature on principal leadership (e.g., Hallinger, 2001; Hallinger & Heck 1996; Southworth, 2002) suggest that twenty years later, the instructional leadership construct is still alive in the domains of policy, research, and practice in school leadership and management. Indeed, since the turn of the twenty-first century, the increasing global emphasis on accountability seems to have reignited interest in instructional leadership. This paper ties together evidence drawn from several extensive reviews of the educational leadership literature that included instructional leadership as a key construct (Hallinger, 2001, 2003b; Hallinger & Heck, 1996b; Southworth, 2002). The paper will seek to define the core characteristics underlying this approach to school leadership and management based upon both conceptual developments and empirical investigation. The review will identify the defining characteristics of instructional leadership as it has evolved, elaborate on the predominant model in use for studying instructional leadership, and report the empirical evidence about its effects. Finally, the paper will reflect on the relationship between this model and the evolving educational context in which it is exercised and how this is reshaping our perspective on instructional leadership. (Contains 1 figure and 3 footnotes.)