This paper critically examines some of the challenges to policy research in education posed by post-modemist and post-structuralist thinking. It starts by characterizing those modernist and structuralist assumptions which have been subject to attack, but suggests that they arc still very much in the ascendancy in the official discourse of educational research (as expressed, for example, by the National Educational Research Forum). Thereafter, key features of the assault represented by the work of Foucault, Derrida and Lyotard are outlined and an account of their destabilizing effect on intellectual work, for individuals and institutions, is offered. Several possible responses are considered. It is argued that policy research poses particular problems because, notwithstanding the messiness of the policy process, there must always come a point of closure on options: decisions cannot be delayed until the epistemological status of educational research is resolved. Researchers must find ways of negotiating the shifting configurations in the relationship between research, policy and practice. This will require both theoretical sophistication and robust engagement with issues that matter to practitioners.