A growing body of academic literacies research has enhanced our understanding of university writing as contested, institutionally situated practice with important consequences, particularly for students as they learn to negotiate the writing demands of university study. Less empirical attention has been paid to the practices of subject academics as they guide, set, and assess student writing. This paper is based on an ethnographically oriented study of 14 UK university teachers in diverse institutional and disciplinary contexts. Data presented illustrate the ways in which competing discourses of writing as "skills" and as "learning" are played out in individuals' practices, in their institutional contexts. Analysis shows how a dominant discourse of writing as "skills" becomes associated with particular ideas about the value of writing work, how and by whom it should be done, and points to consequences for students, teachers and for the role of academic writing in teaching and learning at university.