Three subtypes of autism based on social style have been proposed by Wing: active-but-odd, passive, or aloof. Previous research has shown evidence of an association between IQ and Wing subtype in untreated children and adults. Because IQ changes can accompany behavioral treatment, but often only for a subset of children, social subtype may be related to treatment responsiveness. We administered a social subtyping measure, the Wing Subgroups Questionnaire (WSQ), at various points in treatment to younger children than previously studied with autism in early, intensive behavioral intervention (EIBI). Thirty-seven children in EIBI (aged 39?71 months, amount of EIBI 0?44 months) were assessed to determine whether Wing's three proposed subtypes were found in this sample and whether subtypes were associated with current IQ and change in IQ after a period of EIBI. Results confirmed that all three subtypes were present and correlated with IQ after a period of intervention, as well as with change in IQ. Participants classified as aloof had significantly lower IQ scores and changes in IQ after EIBI than other children. Future studies should extend these findings by examining whether social subtype at pretreatment predicts EIBI outcome.