There has been a good deal of research on Spearman’s hypothesis with regard to Black-White differences in tests of cognitive ability. Most of the research has relied on Jensen’s Method of Correlated Vectors (Jensen, 1998). This method, however, is incapable of rigorously testing competing models that do not involve group differences in g (Dolan, 2000, Dolan & Hamaker, 2001). The purpose of the present paper is to test Spearman’s hypothesis using Multi-Group Confirmatory Factor Analysis applied to three waves of Woodcock-Johnson standardization data. First, using Jensen’s MCV, it is found, for all three standardization waves, that there is a Jensen effect, i.e., positive correlation between the subtests’ g-loadings and the Black-White differences. Secondly, while measurement invariance (MI) was generally found to hold, results from MGCFA using either the high-order-factor or the bi-factor model approach could not reliably confirm that the Spearman’s model fits better than the contra-Spearman’s model. Tentative explanations are provided.