This chapter explores the origins and evolution of supranationality. It contrasts different conceptualizations across various (legal) disciplines by singling out four important contexts which have informed the notion: the turn to modern international law, the establishment of the European Communities, EU law scholarship and the law of IOs. The chapter demonstrates how supranationality is construed through both international law and EU law, which is one of the very reasons its meaning is difficult to pin down. Supranationality, as a doctrinal concept, appears to be trapped by the unresolved quandary of whether EU law is still to be conceived of as being part of international law.