Varied presentations of emotion dysregulation in autism complicate diagnostic decision making and may lead to inaccurate psychiatric diagnoses or delayed autism diagnosis for high-functioning children. This pilot study aimed to determine the concordance between prior psychiatric diagnoses and the results of an autism-specific psychiatric interview in adolescents with high-functioning autism. Participants included 35 predominantly Caucasian and male verbal 10- to 17-year-olds with a confirmed autism spectrum disorder and without intellectual disability. The average age of autism spectrum diagnosis was 11 years old. Lifetime psychiatric diagnoses were established via the Autism Comorbidity Interview, developed to identify comorbid conditions within the context of autism. Autism Comorbidity Interview results were compared to parent report of prior community psychiatric diagnoses. Approximately 60% of prior psychiatric diagnoses were not supported on the Autism Comorbidity Interview; the lowest diagnostic concordance was for prior bipolar disorder and obsessive-compulsive disorder diagnoses. Although 51% of children met Autism Comorbidity Interview criteria for at least one psychiatric disorder, rates of prior diagnoses were much higher, with 77% having at least one prior psychiatric diagnosis and 60% having two or more. Although many participants met criteria for comorbid psychiatric disorders, the majority of previous psychiatric diagnoses were not supported when autism-related manifestations were systematically taken into account. These findings require replication and may not generalize to lower functioning and earlier diagnosed children with autism spectrum disorder. Results emphasize the importance of increasing awareness of the manifestations of high-functioning autism in order to improve accuracy of diagnosis and appropriateness of interventions. (Contains 5 tables.)