This paper explores the challenges for social and cultural historians of education of using documentary films on schools and schooling as a research resource. It draws upon the outcomes of the British Academy-funded Documentary Film in Educational Research project, an international study that focused on developing methodological frameworks for researching school documentaries. The paper offers definitions of the notion of documentary and considers the range of styles and forms that constitute "school documentaries". Among the salient methodological issues examined is the potential for documentary film to be used both as a source and an object of study. These multi-dimensional possibilities raise a series of questions about different status and usages of documentary footage according to research context and about the myriad social, production, genre and technological contexts in which readings of school documentaries are embedded. The paper argues the need for historians of education to develop networks that can contribute not only to academic study of school documentaries but also to the urgent work of archiving and circulating films. (Contains 39 footnotes.)