Over the past two decades, debate over the most suitable leadership role for principals has been dominated by two conceptual models: instructional leadership and transformational leadership. This article reviews the conceptual and empirical development of these two leadership models. The author concludes that the suitability or effectiveness of a particular leadership model is linked to factors in the external environment and the local context of a school. Moreover, the paper argues that the definitions of the two models are also evolving in response to the changing needs of schools in the context of global educational reforms.