In this article we take a critical look at education for sustainable development (ESD), which is a more contested idea than policy makers might have us believe. After a brief examination of the history of the term, we look at the recent Ofsted report into how it is being implemented (or not) in UK schools. We examine why it is a contested term and suggest that science departments might do well to treat ESD with caution and re-examine their contribution and commitment to environmental education.