Despite extensive studies on Homer’s techniques of formulaic composition, thus far the importance of duality in the construction of the Iliad and Odyssey has gone unnoticed. This study demonstrates that duality pervades the epics, from dual magical devices that protect Homeric heroes, to the dual structures upon which the poems are built. By elucidating patterns in Homer’s use of duality, the study develops new insights into the methods of Homeric composition, and powerful new tools for the interpretation of his work.