No Child Left Behind (NCLB) accountability mechanisms have the potential to derail comprehensive school reform (CSR) implementation. For those pursuing CSR, the question is how to reconcile the implementation of NCLB accountability mandates with ongoing CSR efforts. Drawing from longitudinal data from a national study of CSR, this article explores this question. Survey data indicate that schools identified for improvement are no more likely to drop their models than are other CSR schools. Moreover, it appears that when CSR schools are identified for improvement, this identification stimulates a higher rate of model implementation than in schools that are not identified under NCLB. Case study interview data revealed that a district variation in stakeholders' awareness and perceptions of NCLB and the interactions of NCLB accountability mechanisms and CSR sustainability.