Disruptive behavior disorders were assessed in 160 youth aged 13 years, with Autism Spectrum Disorder (ASD, n = 48), intellectual disability (ID, n = 28), or typical development (TD, n = 84). Mothers' reported collateral effects on their psychological adjustment were related to both youth disability status and clinical level behavior disorders. More youth with ASD or ID had clinical level behavior disorders than their TD peers, and their mothers reported significantly higher personal stress and psychological symptoms, as well as lower positive impact of the youth on the family. The youth's clinical level behavior disorders accounted for these differences more than the diagnostic status. Mothers high in dispositional optimism reported the lowest stress and psychological symptoms in relationship to youth behavior challenges.