The aim of the thesis is to examine the idea of disinheritance in six Middle English romances, towards a better understanding of the imaginative work of the romances and the matter of inheritance in the late-medieval imagination. The thesis revises some well-established critical readings of inheritance in medieval romances: namely that the inheritance narrative is fundamentally driven by a reciprocal plot structure, in which an heir loses and then regains an inheritance; and that, as such, the texts sustain a socially and economically conservative ideology of inheritance. I find that disinheritance provides a conceptual framework in the romances for re-imagining rightful heirship: in ways that resist, complicate or subvert medieval legal orthodoxies and particularly the principles of primogeniture. The romances portray the acquisition of heritable property by disinherited, allegedly illegitimate or "unknown" protagonists, through feats of arms or fortuitous happenstance, rather than claims of birthright. While I prioritise close readings of the romances, I also draw attention to historical evidence that suggests a late-medieval gentry readership would have been sensitive to this idea of disinheritance in the texts: in particular, the correlation between disinheritance and opportunity, between aristocratic dynastic instability and non-aristocratic social advancement. The thesis concludes by offering a case study for the political use of this idea of disinheritance, in late-medieval England, and suggesting avenues for further research.