In this chapter I explore the lexicon of border-crossing and foreignness in Chaucer’s poetry and in late medieval England. In a period in which the borders of national territories were rarely firmly established, I explore how affiliation, language, and religion could be indices of belonging. I propose that, for those writing in fourteenth-century English the very definition of belonging and foreignness was measured in local, rather than national, terms, and borders – those symbols of modern colonialism and the nation-state – were almost always porous. Indeed, can we even think in terms of medieval borders when this was a world without formal borders? This essay asks us to consider whether crossing a border always equates to transgression, a change of identity, or an encounter with the Other, through discussions of Chaucer’s poetry, in particular the Knight’s Tale, the Man of Law’s Tale, the Prioress’s Tale and the Shipman’s Tale.