In order to write successfully, students need to understand what it is they are expected to write, why it is written in a particular way and the form that the final text should take. Linguistics research indicates that the ubiquitous essay and report conceal significant disciplinary variation. Educational research reveals variation with regard to assessment and marking of written work within disciplines, between lecturers, across departments, nationally and internationally. We present an interdisciplinary, genre-based model that we have piloted and tested in History at the University of Portsmouth. Our aim is to bring disciplinary, applied linguistic and academic skills expertise to the point where students are taught to write particular assignments. We offer the model for testing in other genres, disciplines and institutions.