This article examines curriculum and practice in Australian secondary classroom music education, in order to trace the inclusion of, and provision for, students with learning orientations based on popular music forms. A 60-year period of curriculum reform, matriculation statistics and literature is surveyed with a focus on the state of New South Wales (NSW), where the 'non-literate' student musician was first acknowledged in curriculum documents dating from the late 1970s at the senior secondary level (Music Syllabus Year 11 and 12: New 2 Unit A Course. Draft Document). Three overlapping eras frame discussion. The first discusses the original post--World War II school curriculum established for Western art music (WAM); the second discusses the period of curriculum reform beginning in the 1960s and 1970s, which leads to the inclusion of popular music at junior secondary levels; and the third is the present era from roughly 1980 onwards, where separate pathways of instruction are maintained for WAM and students with interests in popular and contemporary musics. Legitimation Code Theory (LCT) from the sociology of education is employed, with analysis unveiling a series of historic code shifts and clashes with implications for present practice. An unveiling of these codes explains the cause of ongoing tensions surrounding the inclusion of popular music and musicians in Australian music classrooms and provides foundation for much-needed curriculum development in the NSW context, and potentially elsewhere, where similar dynamics underpin practice in secondary classrooms.