In recent years, policymakers in many states have enacted reforms to teacher evaluation, tenure, and collective bargaining in the traditional public school (TPS) sector. The implications for such changes across the broader labor market for K-12 teachers, however, are often left undiscussed. In this article, we use microdata from 2005-2016 to estimate changes in mobility of charter school and TPS teachers in Michigan, both in regard to inter-sector transfer and teacher exit, during an era of such reform. We find evidence that, following the reforms, charter teachers were less likely -- and TPS teachers more likely -- to exit or transfer sectors.