This Special Issue of Applied Psycholinguistics contains a set of articles on research related to the genetics of developmental language disorders. The guest editors, Mabel Rice and Steven Warren, have assembled cross-disciplinary perspectives on the topic. In doing so, they highlight essential questions concerning the biological mechanism of innateness, the contributions of environment, the measurement of complex behavior, the nature of genetic structure, and the acquisition of language by various groups of young children. The intersection of these questions, one with another, provides a unique contribution of both theoretical and practical consequence for the field of psycholinguistics.