AbstractAimThe receptive language ability of individuals with autism spectrum disorder (ASD) seems to lag behind expressive language ability. Several autism‐related genes may influence this developmental delay. Polymorphism of one such gene, namely, the contactin‐associated protein‐like 2 gene (CNTNAP2), affects receptive language in individuals with language delay. However, the association between CNTNAP2 polymorphism and receptive language in individuals with no language delay remains unclear.MethodsWe included 59 children with ASD and 57 children with typical development in this study and investigated this association using coarse‐grained exact matching.ResultsWe present the first evidence of an association between CNTNAP2 rs2710102 (A‐allele carrier) and reduced receptive language ability in children with ASD whose language development was not delayed. Similarly, among children with typical development, A‐allele carriers had lower receptive language ability, but the difference was non‐significant.ConclusionsIt is possible that the effect of rs2710102 on receptive language ability is larger in the presence of autism‐related genes. Consequently, we speculate that the effect of rs2710102 on receptive language ability would be exerted in combination with other genes. These findings provide new insights into the genetic interactions between mutations associated with common language disorders and ASD and identify molecular mechanisms and risk alleles that contribute to receptive vocabulary. These findings also provide practical guidance in terms of providing candidate genetic markers that may provide opportunities for targeted early intervention to stratify risk and improve prognosis for poor receptive language development in children with ASD.