This paper provides evidence on a large-scale teacher incentive program in the state of São Paulo, Brazil, which awarded group bonuses to teachers and school staff conditional on improvements in student performance. By using a difference-in-differences and triple-differences framework with a series of alternative counterfactual groups, I show that the program had positive effects on student achievement up to seven years after implementation, although improvements vary across grades and subjects. Although it could be expected that free-riding effects increase with the number of teachers in schools, limiting the impact of the program, this does not seem to be the case.