An emotional/behavioral disorder is a mental health disability characterized by intensive internalized behaviors (e.g., anxiety, depression) and/or externalized behaviors (e.g., physical aggression, verbal aggression). Autism is a neurodevelopmental disorder characterized by deficits in social communication and repetitive behaviors (i.e., stereo type). Both of the aforementioned disorders are persistent and may result in a reduced quality of life. Currently, there is a substantial knowledge gap in regards to best practices for students who demonstrate the diagnostic criteria for both disorders concomitantly (i.e., comorbidity). The lack of knowledge regarding co-occurrence of autism and emotional/behavioral disorders in school-age children results in unreliable, invalid diagnostic practices, as well as ineffective instructional programming. The aim of this paper is to provide a review of the literature in order to close this knowledge gap. Thus, the purpose of this paper is to promote valid, reliable diagnostic procedures that lead to efficient individualized supports for children with both autism and an emotional/behavioral disorder. Results of the literature review are discussed in regards to comorbidity of the two disorders (e.g., overlap of phenotypic characteristics) and diagnostic assessment procedures proposed by researchers in the field. Implications for practice and future research are also discussed.