Children with autism spectrum disorder (ASD) are at heightened risk for developing comorbid psychological disorders, including anxiety disorders, which may be further exacerbated by the presence of externalizing behaviors. Here, we examined how structural language and pragmatic language predicted anxiety and externalizing behaviors. Participants were 159 young children (4–7 years old) with ASD and their mothers. Utilizing structural equation modeling we examined associations among structural language, pragmatic language, anxiety symptoms, and externalizing behaviors. Pragmatic language, was inversely related to child anxiety and co-occurring externalizing behaviors. Structural language skills positively predicted child anxiety. These findings suggest that children with ASD may be at heightened risk for anxiety and externalizing disorders due to their pragmatic language deficits.