Evaluation policy typically emphasizes summative judgment, but teacher evaluation also has the potential to provide formative feedback to individual teachers and feedback to focus and strengthen organizational systems to improve teaching practice. This study focuses on feedback provided through the evaluation process, with a particular emphasis on the evaluation of experienced teachers in diverse high schools. Through interviews with teachers and administrators, we explore the ways that teachers and schools use information from teacher evaluations to advance teaching practice through formative and systemic feedback. The four case studies illustrate a range of teacher evaluation practices in high schools. The effectiveness of teacher evaluation as a learning tool is shaped by the broader school context and culture and the extent to which school leaders approach evaluation as a meaningful tool for teacher and organizational learning. (Contains 1 table.)