In recent years, the study of musical cultures has gained popularity as a curricular intervention for increasing cultural diversity in school music curricula. Informed by Michel Foucault's analytics of power-as-effects, this paper examines some of the underlying epistemic premises of the notion of musical culture as it operates in music curricula. Additionally, it considers how this construct's discursive effects align with or contradict its presumed contribution to cultural inclusivity. I use the International Baccalaureate high school music curriculum as my exemplar because of the key role that the notion of musical culture plays in this increasingly popular curriculum. First, I contextualize the notion of musical culture socio-historically, pointing to this construct's Euro-Americentrism. Second, I argue that musical culture leans toward musical formalism. Third, I examine musical culture's presumed distinctiveness, indicating discursive connections to a nineteenth-century, Euro-American conceptualization of cultures as fixed and discrete. Fourth, I examine musical culture's presumed comparability, suggesting that the construct indirectly embraces Euro-American high art music as its frame of reference for analyzing all cultures. Based on this analysis, I suggest approaching the study of musical cultures relationally to render visible the dynamics of power and privilege that shape them. Finally, I consider the potential of abandoning the notion of musical culture altogether in favor of approaches that eschew establishing cultural boundaries.