This chapter discusses the affective domain writer-identity, which is known as self-perception, self-concept, social belonging, possible selves, writer-belief, or as having ownership of your writer’s voice. Theory, research, and educational practices associated with children’s writer-identity and its important role in developing confident and effective writers are explored within this chapter. It includes discussion of the typical behaviours witnessed in a rich variety of educational research and differences observed in the behaviour of pupil-writers who have strong and weak writer-identities. The authors also explore the relationship between children’s funds of identity, funds of knowledge, and writer-identity. Finally, the chapter describes the interconnection between developing apprentice writer-identities and the 14 principles of effective writing teaching and includes examples of the kinds of instructional practice carried out by the most effective teachers of writing.