In the light of increased interest in teachers' professional identities, this paper addresses the under-researched area of teachers' writing identities and examines the factors which influence how primary phase teachers are positioned and position themselves as teacher-writers in the literacy classroom. It draws on case studies of two practitioners in England who seek to model their engagement as writers in order to support young writers; they undertake this through demonstrating writing in whole-class contexts and composing individually alongside children. Data collection methods included classroom observation, interviews, video-stimulated review and examination of written texts. The data show that the writing classroom, in which the practitioners performed and enacted their identities as teacher-writers and as writer-teachers, appeared to be a site of struggle and tension. The research reveals that, whilst institutional and interpersonal factors influence their identity positioning, intrapersonal factors are significant with regard to teachers of writing. Their situated sense of themselves as writers, relationship with their unfolding compositions and emotional engagement, personal authenticity and authorial agency all have saliency in this context. The paper presents a model for conceptualising teachers' writing identities and considers the pedagogical consequences of their participation as writers.