Many Hong Kong Chinese parents believe that music training enhances the academic achievement of their children. The current study investigates the relationship between the extent and outcome of students' music training, their perceptions of the value of the subjects they study and their academic achievement. A total of 286 students in Primary 4, 5 and 6 from one school in Hong Kong reported the extent and outcome of their music training, including the number of instruments they studied, the number of years spent training, highest grade and highest level achieved. For value, students completed a subscale of the Achievement Task Value Questionnaire to measure their "liking and interest," perceived "importance" and "usefulness" of their school subjects. A nested structural equation model showed that, for both boys and girls, the extent and outcome of music training positively predicts academic achievement in Chinese, English and mathematics. Furthermore, the model shows that for both boys and girls, students' perceived value of their school subjects negatively predicts academic achievement in Chinese, and age has a direct and negative effect on mathematics achievement. For girls, age positively moderates the extent and outcome of music training on academic achievement whereas the moderator effect of age on students' perceived value of academic subjects is non-significant. For boys, in contrast, the moderator effect of age on extent and outcome of music training is non-significant, whereas its effect on students' perceived value of academic subjects is negative. In broad terms, the results show that parents are justified in believing that music training is positively related to academic achievement. However, the results differ for boys and girls in connection to the role of age in this relationship. [Copyright of Research Studies in Music Education is the property of Sage Publications Ltd.]