This poster will explore the role of social learning spaces in fostering instrumental music teacher (IMT) development. It draws on one element of my PhD research study-in-progress which aims to add to the understanding of factors shaping IMT identity and agency in Melbourne, Australia, particularly in the under-studied domain of popular music IMTs. This narrative inquiry developed findings through a reflexive thematic analysis of the lived experiences and perspectives described in interviews with seventeen IMTs.The studio instrumental music teaching profession is unregulated, affording many pathways into the role and a diversity of experiences in achieving agency, a sense of identity and in approaches to professional development. The typical lack of formal teaching qualification doesn’t lead to IMTs teaching as they were taught. Instead they learn through activities ranging from informal to formal across a rich and complex social landscape of instrumental music participation, performance, learning and teaching. Wenger’s social learning theory provides a framework for describing such activities as trajectories within and across communities of practice and, more recently (Wenger-Trayner and Wenger-Trayner, 2020), more generalised structures described as simpler and more pervasive ‘social learning spaces’.Wenger’s framework is used to describe the trajectories of learning and identity development that were recalled by research participants. Significantly, musical experiences in a range of social learning spaces prior to commencing IMT work were influential: in families, with friends, at school and other community organisations, in musical collaborations such as garage bands, and with their own instrumental teachers. The role of social learning spaces continued in IMT careers through engagement with peers and colleagues, employers and employees, musical collaborators, Facebook groups and other social media.Perhaps the most important social learning space of all for IMTs is the studio lesson itself when both teacher and student - in the language of Wenger-Trayner and Wenger-Trayner - care to make a difference, engage their uncertainty, and pay attention to feedback. When they collaborate constructively in negotiating meanings and developing their different but complementary competence and identities, both the teacher and student are active learners.