While often cited as one of the most rewarding professions, teaching is demanding, technically challenging, and more closely scrutinized by the public than ever. Although research has helped the education community better understand how children learn and how to support and develop educators, teachers report more dissatisfaction with their jobs and are less likely to stay in the profession beyond five years. This article takes stock of teacher evaluation by exploring the successes and challenges of implementing evaluation systems. It also offers recommendations that the author and colleagues have gleaned from their work with states and districts in designing and implementing systems that support and develop teachers.