School governing bodies in England have considerable powers and responsibilities with regard to the education of pupils. This article explores how power relations operate, within governing bodies, through struggles over which types of knowledge are claimed and valued. The article draws on the analysis of policy and on ethnographic research in the governing bodies of four maintained schools to explore the complex interactions between lay, educational and managerial knowledge. The article suggests that educational and managerial expertise are privileged over lay knowledge. Hence, the concept of "lay" knowledge, which is attached to external governors, is easily coopted by managerial knowledge as it does not have alternative expert knowledge attached to it.