This article describes a comprehensive model of clinical peer review that was established at a large behavioral healthcare organization serving children, adolescents, and adults with developmental disabilities. The purpose of peer review is to provide routine evaluation of practice standards that will produce the highest quality of habilitative care. The major components of peer review address (a) clinical support and administration, (b) intervention policies and procedures, (c) case consultation, (d) utilization of extraordinary procedures, (e) performance improvement projects, and (f) communication at all levels of the organization. This article discusses implementation of the model, including examples and illustrations, and factors that contribute to positive outcome. This approach to peer review represents a systems methodology that can be adopted by behavioral healthcare and human service organizations to build an in-house program of clinical quality improvement. It is a necessary first step in the large-scale implementation of behavioral services.