Recent debates about the status of knowledge in the school curriculum have seen the emergence of attempts to connect curriculum reform to the ideas about 'powerful knowledge' articulated by Michael Young and other sociologists. This article argues that for the case of media education, and specifically its application in secondary schools (in the form of Media Studies), these ideas are not adequate to explain the epistemological principles upon which the project is built. The paper takes a threefold approach to developing an epistemology of media education; firstly, by outlining existing work on the nature of knowledge in media education; secondly, by examining social realist arguments about the way that knowledge is manifested in things like school subjects and canonical knowledge and arguing that media education does not fit these manifestations; and finally by offering some alternative ideas upon which an epistemology of media education may be built.