Scores on the Wechsler Adult Intelligence Scale-Revised (WAIS-R) and Wechsler Intelligence Scale for Children-Third Edition (WISC-III) were compared for 46 youth in the overlapping 16-yr.-age range. Students were administered the tests in a counterbalanced order with an average retest interval of 40 days. Self-reported grade average was also obtained from students. Criteria for parallel tests (equal means, equal variances, equal covariances) were applied in the analyses. WAIS-R and WISC-III summary IQs were parallel, but corresponding subtest scores as a group were not parallel.