This study investigates how instrumental music teachers in a Greek Music Department and a Conservatoire workplace construct their professional identity in the context of their professional practice. With the introduction of instrumental training at the higher education level, the landscape of Greek instrumental music education is rapidly changing. This being the case little theoretical or empirical research has been conducted which examines the practices, knowledge and values that dominate both Conservatoires and the newly established Music Departments. The inquiry is underpinned by the assumption that the construction of identity is a dynamic process, which involves the individual and the wider social, institutional, and cultural context. This research was undertaken in a Greek University Music Department and a Conservatoire. Using an ethnographic case study method, multiple data collection tools were utilised including interviews, observations and documents. The aim was to identify and describe how teachers construct their professional identity in each workplace. The main findings of this inquiry reveal significant links between instrumental music teachers’ identity, knowledge and workplace contexts. Specifically: (1) instrumental music teachers’ professional identity construction was in part influenced by institutional values; (2) the professional knowledge instrumental music teachers drew on differed across institutions in relation to the construction of the more valued identity in each site as either a performer or a teacher; and (3) the construction of instrumental music teachers’ professional identity was a temporal, ongoing process influenced by the resources and constraints specific to their workplaces. Furthermore, (4) instrumental music teachers wove into their practice a strong personal element in the form of self-reflection at the point where teacher and performer identities met. The thesis concludes that music institutions should engage in a critical rethink of their workplaces as settings for the construction of instrumental music teachers’ professional identity. By placing reflective practices (for example, self-reflection) at the intersection where performer and teacher identities meet, a wider range of professional identities can be constructed in institutions that prepare the musical performer. Implications for initial teacher education and continuing professional development are addressed.