The Vineland-3 purports to measure three dimensions of adaptive behavior, but empirical evidence pertaining to its structural validity is lacking. In this study, factor analyses were conducted on the standardization sample data for the comprehensive forms within the 11- to 20-year-old age range. Results did not support the three domain structure of the test and indicated domain scores did not add additional information about an individual's adaptive performance that was not already accounted for by the Adaptive Behavior Composite (ABC) score alone. Practitioners assessing adolescents with developmental conditions should consider using the ABC score within a multimethod assessment protocol for the various purposes of adaptive behavior assessment including the identification of intellectual disability.