This article examines how the social meanings of phonetic variation in a British adolescent community are influenced by a complex relationship between ethnicity, social class and social practice. I focus on the realisation of the HAPPY vowel in Sheffield English, which is reported to be a lax variant [ɛ̈] amongst working-class speakers but is undergoing change towards a tense variant [i] amongst middle-class speakers. I analyse the acoustic realisation of this vowel across four female communities of practice in a multiethnic secondary school and find that the variable’s community-wide associations of social class are projected onto the ethnographic category of school orientation, which I suggest is a more local interpretation of class relations. Ethnographic evidence and discourse analysis reveal that local meanings of the HAPPY vowel vary further within distinctive community of practice styles, which is the result of how ethnicity and social class intersect in structuring local social practices.