A core motivation for the widespread teacher evaluation reforms of the last decade was the belief that these new systems would promote teacher development through high-quality feedback. We examine this theory by studying teachers' perceptions of evaluation feedback in Boston Public Schools and evaluating the district's efforts to improve feedback through an administrator training program. Teachers generally reported that evaluators were trustworthy, fair, and accurate, but that they struggled to provide high-quality feedback. We find little evidence the training program improved perceived feedback quality, classroom instruction, teacher self-efficacy, or student achievement. Our results illustrate the challenges of using evaluation systems as engines for professional growth when administrators lack the time and skill necessary to provide frequent, high-quality feedback.