Teacher quality is an important factor in improving student achievement. As such, policymakers have constructed a number of different credentials to identify high quality teachers. Unfortunately, few of the credentials used in developing countries have been validated (in terms of whether teachers holding such credentials actually improve student achievement). In this study, we employ a student-fixed effects model to estimate the impact of teacher credentials on student achievement in the context of the biggest education system in the world: China. We find that having a teacher with the highest rank (a credential based on annual assessments by local administrators) has positive impacts on student achievement relative to having a teacher who has not achieved the highest rank. We further find that teacher rank has heterogeneous impacts, benefiting economically poor students more than non-poor students. However, whether a teacher attends college or holds teaching awards does not appear to provide additional information on teacher quality (in terms of improving student achievement).