This policy brief examines the major trends in the development and use of open educational resources (OER). It notes the growing expansion in the quantity of OER and how that is already impacting learners, teachers, educational institutions and governments. It argues that to be truly successful in improving educational opportunity and attainments OER are a necessary stimulus for a broader shift in opening up educational policies and practices. It concludes that such a cultural change needs a wider societal change to thinking of educational resources as largely a public rather than a private good.