The work of renewing curriculum in music education faces the inertia of current curricular practices and an education reform climate that is unfavorable toward such work. This article suggests that the development of music teacher agency is central to combating these challenges, and that the development of such agency relies on today's professional associations. I explore the conditions under which such associations build member agency, examine the National Association for Music Education as a case study, and argue for the importance of professionalism as a reform logic. I then offer recommendations that address how teacher associations can better assert their particular role in leading curriculum renewal in today's complex and rapidly changing environment.