This paper discusses recent developments in the senior music curriculum in New Zealand. I suggest that school music is in transition from its clearly defined origins to its "regionalisation" by new content and knowledge. The concepts of knowledge differentiation and verticality are considered in relation to the subject's now diverse range of curriculum segments, and I argue that the varied progression requirements of these segments combined with an "emptying out" of significant aspects of knowledge within an outcomes-based curriculum presents significant challenges for curriculum construction and pedagogy. Also vying for space within the curriculum are elements of informal music learning. These challenges need to be carefully considered in light of recent social realist critiques which highlight the significance of the relationship between knowledge structures, curriculum, pedagogy and student access to powerful knowledge.