This study examined mental health risk/protective factors for DSM-IV psychiatric symptoms in children with an autism spectrum disorder (ASD) and their contribution to functioning separate from ASD symptom severity. Mothers/teachers completed measures of risk/protection and social, adaptive, and school functioning in 6- to 12-year-olds with a diagnosed ASD (N = 238). Bivariate correlations and simultaneous regression analyses indicated a unique pattern of predictors for attention-deficit/hyperactivity disorder, aggression, anxiety, and depression symptoms. Moreover, psychiatric symptoms differentially predicted social and school performance. Findings indicate that co-occurring psychiatric symptoms and their associated mental health risk/protective factors may have important clinical implications and generally support a biopsychosocial model of psychopathology in children with an ASD that appears to share many similarities with models for nonASD children.