We examined the associations between academic achievement and arts involvement (access to a musical instrument for the child at home, participation in unspecified after-school arts activities) in a sample of 2339 11-12-year-olds surveyed in the USA between 1998 and 2008. We compared the contributions of these variables to other kinds of cognitive stimulation at home (e.g. books), participation in after-school sports, and socioeconomic factors. Involvement in after-school arts was positively related to academic achievement only for those children who also reported access to a musical instrument. Access to a musical instrument predicted academic achievement independently of socioeconomic status. We consider the possibilities that the results may be indicative of differing parental attitudes in homes with musical instruments and/or a causal link between instrumental music learning and academic achievement.