This brief from the Learning Policy Institute examines how state and district policies influence principals’ access to high-quality learning opportunities during preparation and throughout their careers. It identifies a set of policy levers states and districts can utilize to promote principal effectiveness, including standards for leadership practices, preparation programs, and licensure and investments in induction programs, leadership pipeline programs, and professional development. These levers are particularly important given research findings emphasizing the importance of increasing access to high-quality, equity-oriented, preservice-based learning opportunities for creating effective school principals. The report’s implications are most salient for preparation program administrators aimed at principals and policymakers interested in how they can better support principal effectiveness. The brief is based on a more expansive report on principal preparation, Developing Effective Principals: What Kind of Learning Matters?