Initial teacher education must respond to the demand that newly qualified teachers are able to teach inclusively. This response has been the creation of opportunities for learning in coursework and field experiences. Research has identified the impact of these initiatives and also revealed challenges. One such challenge is the lack of a coherent conceptual framework that leads to a disconnection between coursework and field experiences. We frame this challenge as the need for cumulative knowledge-building as part of developing inclusive teaching as a knowledge-based practice. Drawing on the conceptual repertoire of Legitimation Code Theory, we argue for programme design that systematically develops pre-service teachers' conceptual and contextual understandings of inclusive teaching through a structured interplay between coursework and field experiences. Assessment plays an important role in showing students what is important in a curriculum, so we suggest approaches to assessment of inclusive teaching competence that supports knowledge-building.