This article questions the notion of global citizenship, arguing that it is not possible in strictly legal terms as there is no global state that could guarantee citizenship. However, metaphorically there are several possible conceptions of global citizenship. These are examined along with associated notions of global education. The issue of for whom such global citizenships might be possible is addressed, as is the issue of what citizenship might mean in failed states. It is suggested that international schools will respond variously to this variety of conceptions of global citizenship, and that where they locate themselves within this complex of metaphors will have major impact on their presentation of curriculum, pedagogy and assessment.