Although links between music training and cognitive abilities are relatively well-established, unresolved issues include the generality of the association, the direction of causation, and whether the association is mediated by executive function. Musically trained and untrained 9- to 12-year olds were compared on a measure of IQ and five measures of executive function. IQ and executive function were correlated. The musically trained group had higher IQs than their untrained counterparts and the advantage extended across the IQ subtests. The association between music training and executive function was negligible. These results provide no support for the hypothesis that the association between music training and IQ is mediated by executive function. When considered jointly with the available literature, the findings suggest that children with higher IQs are more likely than their lower-IQ counterparts to take music lessons, and to perform well on a variety of tests of cognitive ability except for those measuring executive function.