The concept of teacher identity is increasingly recognized as a critical determinant of how teachers perceive themselves, how they are seen by others, and how they choose to act. It follows that teacher identity is a key determinant of the scope and nature of teachers’ professional work as well as their willingness to embrace change and engage in faculty development. Teacher identity is shaped by teachers’ history of participation in institutional and professional cultures as well as their involvement in workplace communities of practice. Given the contingent nature of teacher identity, and its powerful influence on teacher development, faculty developers should know how to nurture and support the promotion of sustainable teacher identities in clinical and academic workplaces. This chapter will explore the concept of teacher identity formation from cognitive and sociocultural perspectives, and will describe established and novel faculty development approaches designed to enhance teacher identity.