Research continues to highlight discrepancies between clinical diagnoses of Autism Spectrum Disorder (ASD) and determination of special education eligibility for services within school settings. However, limited research has been conducted on the impact of those discrepancies for the identification of appropriate services within schools. The aim of the current study is to examine students' characteristics (e.g., language, social emotional) associated with educational eligibility and clinical diagnoses. More specifically, the study examines characteristics differentially associated with ASD diagnoses to inform targeted evidence-based interventions. The study accessed data from a four-year cluster-randomized trial of 283 students with and without reported ASD diagnosis. The results of the study demonstrate that the educational eligibility of Autism did not differentiate between students with and without autism on any of the measured characteristics including language, peer and social competence, academics, and aggressive behaviors. However, the Autism Diagnostic Observation Schedule, second edition (ADOS-2; Lord et al. in Autism diagnostic observation schedule. Western Psychological Services, Torrance, CA, 2012) classification was a more sensitive diagnostic measure for characteristics associated with autism. Implications for research, practitioners, and schools are discussed.