While choices of musical repertory are key to challenging the historical ethnocentrism of school music curricula, ethnocentrism manifests as powerfully in the way a curriculum defines and structures musical knowledge. This article examines the knowledge divisions used to structure one of the most popular and reputable high school music curricula worldwide: the International Baccalaureate (IB). My analysis indicates that, while IB music gestures rhetorically to cultural and epistemic pluralism, its primary knowledge divisions--Musical Perception, Creating, and Performing--are fundamentally rooted in modern Euro-American conceptions of musical knowledge and ways of knowing. This study demonstrates the importance of explicitly acknowledging the epistemic foundations of music curricula's foundations so that teachers and their students can better decide how they want to engage with the knowledge presented.