The international community now recognises the impact of ‘gender-based harms’ of conflict, the armed violence that targets or disproportionately affects women. It also acknowledges the obligation to prosecute these crimes. However, many claim that international justice continues to fail women victims of war. So are we witnessing a new age of accountability for these crimes against women? Or does international criminal justice reproduce existing gender inequalities? Some fifteen years after the establishment of the first international criminal tribunal, these questions remain unanswered. The proposed research takes up these fundamental problems of gender and justice, and develops an innovative research ‘gender justice’ framework. This framework engages with the thoroughly social nature of gender and justice. It examines how social actions and norms construct categories of the person, the harmful, and the just by building a social theory of ‘gender justice’. This theory investigates the nature of gender harms, identifies how sexual differentiation shapes law, and provides a normative model of gender justice. It is built upon a unique socio-legal case study of the international and national prosecution of sexual violence in the Yugoslavian conflict. Sexual violence in armed conflict is the most pervasive and visible of criminalised gender-based harms. It is also the area in which international law claims to have made its most significant advances. This case study provides a systematic and rigorous means of building models of highly complex social processes, and of developing explanatory and normative theories of ‘gender justice’. The project proposes a new framework that takes ‘gender justice’ as an object of research. It creates a new field of inquiry, with specific research problems, new conceptual and methodological frameworks, and identifiable normative criteria. Ultimately, the project aims to change our ideas of ‘gender justice’ itself.