Using multi-group covariance and means structure analysis (MG-CMSA), this study investigated whether sex differences were present on the Dutch WAIS-III, and if so, whether these sex differences were attributable to differences in general intelligence (g). The sample consisted of 294 females and 228 males between 18 and 46 years old. Both first and second order common factor models were fitted, the latter including g as second order factor. The results indicated that on the level of the subtests, females outperform males on Digit-Symbol Substitution, and males outperform females on Information and Arithmetic. In addition, the subtests Information proved to be biased in favor of males. With respect to the first order common factors, no sex differences were found with respect to the factor Verbal Comprehension (once Information was effectively removed from the model). Yet, males outperformed females on the factors Working Memory and Perceptual Organization, and females outperformed males on Perceptual Speed. These sex difference on the level of the first order common factors were however not attributable to sex differences in g. Summarizing, the present study showed that males and females do differ with respect to specific cognitive abilities, but that g cannot be viewed as the source of these differences. © 2005 Elsevier Inc. All rights reserved.