This qualitative study examines how principals support the implementation of the Three-Block Model of Universal Design for Learning (Katz, 2012a), a framework for inclusive school reform. The ways that principals can support inclusive practice may include the way they use systems and structures that fall under their control (Katz, 2012a). Instructional leadership also plays a crucial part in implementing inclusive school reform (Leithwood & Riehl, 2005). Data were collected through semi-structured interviews with five Manitoba principals involved in implementation of the Three-Block Model of UDL. Principals were asked about leadership and how they manage systems and structures under their control. Recommendations for practice are made, including the need for the school to be organized to support inclusive practice, for principals to make developing people a key task, and for principals to be highly involved in classroom instruction within the school.