The purpose of this paper was to update the psychometrics of the "Matson Evaluation of Social Skills for Youngsters" ("MESSY") with children with Autism Spectrum Disorders (ASD), specifically with respect to internal consistency, split-half reliability, and inter-rater reliability. In Study 1, 114 children with ASD (Autistic Disorder, Asperger's Syndrome, or Pervasive Developmental Disorder--Not Otherwise Specified) were assessed using the "MESSY". Participants ranged in age from 2 to 16 years. Study 1 found excellent internal consistency, and split half reliability. Using "MESSY" scores from two caregivers of 33 children, Study 2 found that the "MESSY" demonstrated moderate to high inter-rater reliability. As such, this study established the internal and inter-rater reliability of the "MESSY" for use among children with ASD. (Contains 1 table.)