In a large field experiment I study how repeated public praise impacts the short and long run performance of 900 teachers in 39 schools. For both recipients and non-recipients of recognition, I analyze the effect of repeated public praise on performance as measured by student grades, attendance, and performance on anonymously graded high-stake exams. In a random half of the schools, the best teachers (according to teacher value added) are praised in an online message posted on the school messaging board. When teachers are praised (not praised) in the first round, their students perform significantly better (worse) in subsequent months. Using the fact that praise is repeatedly given, I test different mechanisms that could explain teacher behavior. Results are in line with teachers having status concerns, and learning about their relative performance through praise. Recognition has large and persistent effects, explained by real increases in effort, as opposed to teachers “cheating” on student assessments.