Children with autism spectrum disorder (ASD) and children with attention deficit/hyperactivity disorder (ADHD) both experience behavioral and social difficulties. Prior research has shown that when these disorders co-occur, behavioral symptoms associated with both disorders may be more severe. There is only limited research on the impact of ASD + ADHD comorbidity on social functioning. The present study investigated social impairment in 282 children diagnosed with ASD, ADHD, or ASD + ADHD. No significant differences in social impairment were found between the ASD and ASD + ADHD groups. This study contributes to extant literature indicating mixed findings in regard to social functioning amidst the ASD + ADHD comorbidity.