This study examined the reliability and criterion-related validity of parent ratings on the Adapted Skillstreaming Checklist (ASC) for a sample of 275 high-functioning children, ages 6–12 years, with ASD. Internal consistency for the total sample was 0.92. For two subsamples, test–retest reliability was very good at the 6-week and good at the 9-month intervals. Child age, IQ, and language abilities were unrelated to the ASC score. The ASC total score was inversely and strongly related to parent ratings of ASD symptom severity. Significant positive correlations (moderate-to-high) were found between the ASC and prosocial skills scales and significant negative correlations (low-to-moderate) with problem behavior scales on a broad measure of child functioning. Implications and suggestions for future study are discussed.