The aim of this study was to examine the internal consistency, inter-respondent reliability, and convergent and divergent validity of the Psychoeducational Profile-third edition Caregiver Report (PEP3-CR) in children with Autism Spectrum Disorders (ASD). We examined the internal consistency on 66 mothers of children with ASD who completed the PEP3-CR. Inter-respondent reliability was examined on 46 pairs of mothers and fathers who completed the PEP3-CR independently within one week. Moreover, 64 children were administered the Psychoeducational Profile-third edition Performance Test (PEP3-PT) and 20 children and their parents were administered the Childhood Autism Rating Scale (CARS) and the Vineland Adaptive Behavior Scale (VABS) to examine the convergent and divergent validity of the PEP3-CR. The Cronbach's alpha of the PEP3-CR subtests, ranging from 0.83 to 0.85, indicated sufficient internal consistency. The intra-class correlation coefficient (ICC) of the two parents, ranging from 0.66 to 0.79, indicated moderate inter-respondent reliability. The correlations between the PEP3-PT, CARS, VABS and the PEP3-CR supported the convergent and divergent validity of the PEP3-CR. Therefore, the PEP3-CR is a reliable and valid caregiver report for assessing adaptive functioning and autistic behaviors in children with ASD. (Contains 3 tables.)