We investigated the presentation and correlates of hoarding behaviors in 204 children aged 7–13 with autism spectrum disorder (ASD) and comorbid anxiety or obsessive-compulsive disorder (OCD) symptoms. Approximately 34% of the sample presented at least moderate levels, and with 7% presenting severe to extreme levels of hoarding. Child gender predicted hoarding severity. In addition, child ASD-related social difficulties together with attention-deficit and hyperactivity disorder symptom severity positively predicted hoarding controlling for child gender and restricted and repetitive behaviors. Finally, child anxiety/OCD symptoms positively predicted hoarding, controlling for all other factors. These results suggest hoarding behaviors may constitute a common feature of pediatric ASD with comorbid anxiety/OCD, particularly in girls and children with greater social difficulties and comorbid psychiatric symptom severity.