Previous studies have reported dysbiosis in the gut microbiota (GM) of children with autism spectrum disorders (ASD), which may be a determining factor on child development through the microbiota-gut-brain axis. However, it is not clear if there is a specific group of dysbiotic bacteria in ASD. The aim of this study was to carry out a meta-analysis on the studies that analyze GM in children with ASD. 18 studies fulfilled our selection criteria. Our results showed a lower relative abundance of "Streptococcus" (SMD[subscript +] = -0.999; 95% CI -1.549, -0.449) and "Bifidobacterium" genera (SMD[subscript +] = -0.513; 95% CI -0.953, -0.073) in children with ASD. Overall, the "Bifidobacterium" genera is involved. However, differences found between studies are attributed to factors such as reporting bias.