The current study sought to understand the relation between diagnostic status (autism spectrum disorders [ASD] versus typically developing) and internalizing problems in children with and without co-occurring attention deficit hyperactivity disorder (ADHD) symptoms. Participants were 88 children, ages 3:0-6:11, their parents and teachers. Findings indicated that ADHD symptoms moderated the relation between diagnostic status and depressive and somatic symptoms. High ADHD symptoms in children with ASD were associated with increased depressive and somatic symptoms compared to children with typical development. Findings suggest poor prognostic outcomes for children with ASD and co-occurring ADHD symptoms and highlight the need for early identification and targeted intervention.