Integrating theoretical knowledge within teacher education has often been portrayed as difficult, with previous studies reporting student teachers' ambivalence, or even scepticism, about the value of research findings and theory to classroom practice. Moreover, the nature of teachers' professional knowledge is itself uncertain and highly complex. This paper reports on the developing conceptions held by a group of postgraduate student teachers about the relationship of theory to classroom practice in learning to teach. The data are drawn from a small-scale longitudinal case study. They capture participants' preconceptions about theory before beginning training and subsequent developments through the course and into the first teaching post. The research finds these students to be far from naïve at the outset, entering training open to a range of forms of learning, with a positive view of the potential contribution of theory to practice. Alongside a growing appreciation of the complex, situated and contested nature of theory, the data suggest that theory comes to be increasingly valued over time. As newly qualified teachers, the participants not only see theory as integral to their practice, but recognise the important, largely unanticipated, role of the university in this process. As a result of these insights, potential considerations for course design are offered, at a time when teacher education in many countries is becoming more school-based and new forms of partnership are being developed.