This article argues for a fundamental raison d’être reconceptualization of international investment law (IIL) through Martha Fineman’s ‘vulnerability theory’. The theory helps identify the structural sources of IIL’s shortcomings, whilst philosophically challenging the one-sided view that foreign investors are entitled to protections, but are free from obligations vis-à-vis the communities affected by their undertakings. Emphasizing the productive power of the state to take positive action that acknowledges ordinary citizens’ embeddedness within, and dependence upon, surrounding structures, the vulnerability theory challenges the hegemonic perception of the state as a source of danger – a view which has hitherto undermined both the potency and the enforceability of investor obligations. Used as a heuristic device in studying both IIL’s existing structures and the potential avenues for reimagining it, Fineman’s theory not only shines a novel light on the foundational premises of IIL, but also grants theoretical traction to existing ideas about improving the system.