As a result of a documented decline in student engagement with curricular music in recent decades, which has called into question traditional approaches to music learning and teaching, theorists have advocated for a reconceptualisation of 'curriculum' in music education. This expanded understanding challenges teachers to reject the 'instruction manual' approach, to engage more actively and creatively with music content and pedagogical practices and to re-evaluate their relationship with students. While much has been recommended to guide teachers in relation to this reconceptualised role, contemporary research in many countries reports on an ever-deepening crisis regarding the state of school music and the constraining impact of top-down policy decisions on teachers' autonomy and agency. Placing the teacher at the centre of the curriculum process, the aim of this article is to identify and explicate the theoretical and practical competencies that will support teachers in developing their curricular know-how and their capacity to make informed pedagogical decisions which align with contemporary understandings of curriculum. This discussion also outlines implications for initial music teacher education and continuing professional development. To set the context, we begin by giving an overview of the changes in curriculum theory and how this impacts the role of the teacher.