In this chapter, we briefly review the use of rats as a genetic model for the study of behavior. Rats were the first mammalian species used for genetic and biological research. Since the development of the first inbred rat strain in 1909, more than 700 unique inbred and outbred rat lines have been generated. Although rats have been somewhat eclipsed by mice in the last few decades, a renewed appreciation of the advantages of rats for behavioral and other types of research is upon us. We briefly review the pertinent characteristics of the rat and highlight the key advantages of using the rat to examine behavioral phenotypes.