We sought to clarify the commonly accepted link between music training and cognitive ability. Professional musicians, nonprofessionals with music training, and musically untrained individuals (N = 642) completed measures of musical ability, personality, and general cognitive ability. Professional musicians scored highest on objective and self-report measures of musical ability. On personality measures, professional musicians and musically trained participants scored similarly but higher than untrained participants on agreeableness, openness-to-experience, and the personality metatrait stability. The professionals scored higher than the other 2 groups on extraversion and the metatrait engagement. On cognitive ability, however, they were indistinguishable from untrained participants. Instead, musically trained nonprofessionals exhibited the highest cognitive ability. In short, professional musicians differed from other individuals in musical ability and personality, but not in cognitive ability. We conclude that music training predicts higher cognitive ability only among individuals who do not become professional musicians and offer possible explanations.