In this study, the authors used structural equation modeling to investigate relationships between ability constructs from the "Wechsler Intelligence Scale for Children-Third Edition" (WISC-III; Wechsler, 1991) in explaining reading and mathematics achievement constructs on the "Wechsler Individual Achievement Test" (WIAT; Wechsler, 1992). Participants comprised the nationally stratified Linking sample (N = 1,116) of the WISC-III and WIAT. Relating the latent ability variables to the latent achievement variables showed that psychologists must go beyond "g" in order to meaningfully understand children's trait performance on the WISC-III. Results for reading indicated psychologists must pay attention to the constructs of "g" and Verbal Comprehension, and for mathematics, that they are obliged to consider "g" and Freedom From Distractibility. Results are discussed in terms of their theoretical, applied, and treatment-related implications.