Districts around the country are grappling with teacher shortages. Given that attrition accounts for nearly 90% of the demand for new teachers, strategies that increase teacher retention are particularly important. Principal leadership plays a significant role in teacher turnover. Teachers identify the quality of administrative support as a key factor in decisions to leave a school. In addition, teachers point to the importance of school culture and collegial relationships, time for collaboration, and decision-making input--also areas in which the principal plays a central role. Principals tend to be weaker in high-poverty, low-achieving schools, where principal quality can have an even greater bearing on teacher attrition. Local, state, and federal policymakers have a role to play in recruiting and training principals. The passage of ESSA provides one such opportunity, as local and state policymakers can leverage federal ESSA funding to strengthen principal preparation and development. [The content of this brief draws on findings from "Supporting Principals' Learning: Key Features of Effective Programs" (ED606829); "A Coming Crisis in Teaching? Teacher Supply, Demand, and Shortages in the U.S." (ED606666); and "Solving the Teacher Shortage: How to Attract and Retain Excellent Educators" (ED606767).]