The authors consider the potential and promise of the 2000 UNESCO Earth Charter for the work of the religious educator in situating a 'common' ethical core in a global world. It is argued that the Charter represents a courageous attempt to negotiate a global ethic of universal and multi-faceted responsibility based on the foundation of membership of the human family in a common home: the Earth. Both the vision and the methodology of the Charter witness to a capacity for moral discourse across the boundaries of difference. As such, the Charter merits sustained and serious philosophical and theological critique. Accordingly, the religious educator must sensitively support pupils in the challenging task of responding to the expanded ethical landscape that the Charter presents.