The autism spectrum is characterized by genetic and behavioral heterogeneity. However, it is still unknown whether there is a universal pattern of cognitive impairment in autism spectrum disorder (ASD) and whether multiple cognitive impairments are needed to explain the full range of behavioral symptoms. This study aimed to determine whether three widely acknowledged cognitive abnormalities (Theory of Mind (ToM) impairment, Executive Function (EF) impairment, and the presence of a Local Processing Bias (LB)) are universal and fractionable in autism, and whether the relationship between cognition and behavior is dependent on the method of behavioral assessment. Thirty‐one high‐functioning children with ASD and thirty‐seven children with neurotypical development (NTD), comparable in age, gender and Intelligence Quotient (IQ), completed several tasks tapping into ToM, EF, and LB, and autistic symptomatology was assessed through parental and teacher questionnaires, parental interview and direct observation. We found that ToM and EF deficits differentiated the groups and some ToM and EF tasks were related to each other. ToM and EF were together able to correctly classify more than three‐quarters of the children into cases and controls, despite relating to none of the specific behavioral measures. Only a small subgroup of individuals displayed a LB, which was unrelated to ToM and EF, and did not aid diagnostic classification, most likely contributing to non‐diagnostic symptoms in a subgroup. Despite the characteristic heterogeneity of the autism spectrum, it remains a possibility therefore that a single cognitive cause may underlie the range of diagnostic symptoms in all individuals with autism. Autism Res 2016, 9: 1328–1339. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.