This paper constructs a theoretical argument to frame feedback as a relational concept. It addresses contemporary concern that formative assessment, of which feedback is a part, is under theorised. The arguments presented link to existing theoretical and research evidence. The paper also challenges the dominant policy discourse in high stakes assessment contexts in which feedback is typically seen in technised ways to serve the need to raise measured pupil outcomes. Vygotsky's notion of the zone of proximal development is explored as a relational space in which both teachers and learners understand differences between learning 'now' and learning 'next'. Extending Vygotsky's perspective, a socio-cultural perspective is offered, by considering the role of 'others', 'language', 'activity' and 'identity', as part of the process of sharing and understanding feedback in classrooms. The work of Holland et al. (1998), Bakhtin (1986) are central to the developing argument. The paper reveals feedback as a complex situated process, requiring mediated dynamic interaction, where feedback is appropriated as a cultural artefact by its participants. The implications of such an articulation demands a greater sense of understanding pupils' roles in feedback and the importance of teachers enabling pupils to see themselves in new ways as future learners.