Teacher turnover is an enduring concern in education policy and can incur substantial costs to students. Policies often address turnover broadly, yet effects turn on net differences in the effectiveness of exiting and entering teachers, in addition to the disruption dealt to classrooms. Recent research has shown mixed effects of teacher evaluation policies, but even where evaluation-induced differential turnover initially benefited students, gains might disappear or reverse as the stock of less effective teachers exits and if more effective teachers view high-stakes evaluation as burdensome. We examine evaluation-induced changes to the composition of exiting and entering teachers in Washington, D.C., the net effect of turnover on student achievement, and the role that evaluation played in teacher turnover. We find that turnover continues to improve teaching skills and student achievement, although effects have diminished. We find little evidence that high-performing teachers' exit is associated with the evaluation system.