Autism spectrum disorder (ASD) as a synaptopathy is revealed to be pertained to aberrant glutamatergic neurotransmission. Glutamate receptor, metabotropic 7 (GRM7), a receptor coding gene of this pathway, is a new candidate gene for autism. The aim of this study was to examine if there is a relationship between genetic variants rs779867 and rs6782011 of GRM7 with ASD. The present research was designed as a population‐based, case–control study including 518 ASD patients versus 472 control individuals. The results showed that the frequency of rs779867 G/G genotype was significantly higher in ASD patients compared to healthy controls (P = 0.0001). Also, the G allele of this SNP was found to be significantly more frequent in the patients than control group (P = 0.0001). Haplotype analysis exhibited significant association of two estimated block of rs6782011/rs779867 in ASD patients versus control group. We found higher significant frequency of GT haplotype and lower frequencies of AT and AC haplotypes in the patients group compared to healthy controls (P = 0.001, P = 0.006, and P = 0.05, respectively). Our study indicated that the rs779867 polymorphism is associated with ASD; thus, results of this study provide supportive evidence of association of the GRM7 gene with ASD. Autism Res 2016, 9: 1161–1168. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.