There are few studies offering a comprehensive understanding of the relationship between popular music and youth cutting across both school and leisure sites. This article bridges missing links between girls and boys as performers and listeners of popular music in school and leisure sites. The aim is to investigate how high school pupils' discourses on popular music take place in different settings (i) with relation to gender, and (ii) with relation to the nature of musical practices. Through my ethnographic study conducted in Japan, pupils' techniques for employing popular music in various sites are clarified; firstly, in the formal site (classroom); secondly, in the semi-formal site (brass band club in school / high school band event); thirdly, in the informal site (boys as performers / visual band costume play gatherings). Three categorisations of popular music are theorised: ‘personal’, ‘common’ and ‘standard’. Boys' strategies for negotiation and differentiation, and girls' tactics for utilising common music in order to conceal their own personal music are found in each site.