As youth with autism spectrum disorder (ASD) are more likely to experience anxiety than youth in the general population, investigation of associated factors is important for diagnosis and treatment. The present study extended prior research by examining factors associated with caregiver-reported anxiety in 2662 youth (mean age = 8.82 years) with ASD. Logistic regression analyses indicated increases in age, social problems, and cognitive functioning predicted high anxiety group membership. Cognitive functioning moderated the relation of adaptive social behaviors and anxiety. Results from the present study provide support for previously identified factors associated with anxiety; however, further investigation is necessary to uncover additional factors and to explore their relation to anxiety across individuals with ASD with varying levels of cognitive functioning.