Although music training has been related to better school performance, the processes that may mediate this improvement are unknown. Given that study habits and techniques are one of the variables most closely related to academic achievement, the present study analyzed the differences in study habits and techniques between children with and without musical training, checking whether the age at which training began is a significant variable and whether study habits and techniques act as a mediator between musical training and academic achievement. A total of 132 children aged 9-12 years from the Autonomous Community of the Basque Country were studied using the Questionnaire of Habits and Study Techniques and school grades. Significant differences were found in the "attitude toward study," "exams and exercises"; "personal and environmental conditions for study"; and general study habits and techniques in favor of children with musical training. In addition, children who started training before the age of seven showed better results in study habits and techniques. In turn, study habits and techniques significantly mediated the relationship between music training and academic achievement. Therefore, music training, especially before the age of seven, seems to have a beneficial effect on academic achievement, which could be explained, at least in part, by study habits and techniques.