Autism spectrum disorders (ASD) and schizophrenia (SZ) are both associated with response inhibition impairment. However, the relative pattern of deficits in these two disorders remains unclear. Twenty-three male children with ASD, 23 male children with SZ, and 32 typically developing male controls were recruited to complete a set of tasks measuring response inhibition in the visual, auditory, and verbal domains. We found that visual, auditory, and verbal response inhibitions were impaired in both children with ASD and children with SZ. Compared with typically developing controls, children with ASD made more commission errors whereas children with SZ responded much slower in the visual response inhibition task. Both clinical groups showed comparable impairment in verbal response inhibition, but children with SZ were more impaired in auditory response inhibition than children with ASD. These different patterns of response inhibition deficit between male children with ASD and SZ may help to differentiate between these two disorders and may be potential targets for intervention. Autism Res 2019, 00: 1-8. (c) 2019 International Society for Autism Research, Wiley Periodicals, Inc. Lay Summary In this study, we found that male children with autism spectrum disorder (ASD) made more commission errors whereas male children with schizophrenia (SZ) responded much slower in the visual response inhibition task. Both clinical groups exhibited comparable impairments in verbal response inhibition, but male children with SZ were more impaired in auditory response inhibition than male children with ASD. Our findings provide potential targets for intervention.