Teacher performance assessment refers to the evaluation of teaching practices using measures that gather authentic evidence of the day-to-day tasks of teaching. Performance assessment is sometimes used within the context of accountability policy. There is much debate about how to evaluate teaching quality, teacher effectiveness, and accountability for classroom learning. Although many express concerns about an overemphasis on standardized testing as the sole measure of student learning, there is a strong call by the public to ensure that all teachers are well prepared to meet the learning needs of America’s increasingly diverse learners. This entry presents a description of a recent innovation in teacher performance assessment known as edTPA and its use as a measure of teaching effectiveness for early childhood educators.