This study examined sex differences in externalizing and internalizing symptoms of children with ASD without intellectual disability (ID). The sample (n = 80) included 40 girls and 40 boys, ages 6–12 years, with ASD (without ID) matched on age and IQ. Externalizing and internalizing symptoms were significantly elevated for this sample (girls and boys) relative to normative estimates for all the scales (hyperactivity, aggression, anxiety, and depression) except conduct problems. No significant differences were found between girls and boys for either externalizing symptoms or internalizing symptoms (based on standard score and raw score analyses). Implications for clinical practice and future research are discussed.