Recent proposals pin hopes on the 'responsibility to protect' (R2P) as holding tremendous promise for the protection of internally displaced persons (IDPs). This essay examines the relationship between R2P and IDP protection and explores the protection potential – and possible limitations – of marrying these two concepts. It traces their shared normative underpinnings, the historical roots of which run deep, and considers the added value that R2P can bring. It then reviews how the central tenets of R2P borrowed and built upon the conceptual framework that was crafted and cultivated over the preceding decade to guide international efforts for the protection of IDPs. Finally, it considers how R2P holds a potential key to unlock and unblock some of the persistent obstacles to an effective UN response for securing protection for IDPs, at least in certain situations when prompt protective action is particularly critical. The conclusion is that R2P and IDP protection are a good match overall, considering not only their commonalities and thus natural compatibility, but also the important ways in which they differ and can complement one another to ensure a more comprehensive protection response.