The objective of this study was to evaluate the effectiveness of simultaneous training for children with autism spectrum disorder (ASD) and their parents, with a focus on social skills enhancement (STSSE) by evaluating behavioral changes in children with ASD and changes in family functioning. STSSE was conducted on 17 children of elementary school age with ASD and their parents. Changes in scores on the social skills scale for education (SS-scale), the child behavior checklist, the Feetham Family Functioning Survey (FFFS), and the confidence degree questionnaire for families (CDQ) were used to assess the effectiveness of STSSE. Improvements were seen for "Communication Skills" on the children's SS-scale (p = 0.029). Significant improvements were seen in the mothers' FFFS scores for "The 4th factor: illness and worries" (p = 0.016) and in the median CDQ scores for one of 18 items after STSSE (p = 0.01). Although additional studies with larger sample sizes will be necessary before these findings are generalizable, the positive changes seen in both parents and children as a result of STSSE are promising.