Language has featured prominently in contemporary social theory, but the relevance of this fact to the concerns of Applied Linguistics, with its necessary orientation to practical issues of language in context, represents an ongoing challenge. This article supports the need for a greater engagement with theory in Applied Linguistics. It considers the ongoing debate about the nature of Applied Linguistics as a field and the role of theory within it. The article concludes with a call for re-engagement with theory in the humanities, in particular poststructuralism.