This work aims to delineate the extent of state obligations in international law for preventing rape by enacting criminal laws in relation to it, but it will mainly be concerned with examining whether such responsibilities require the adoption of a particular definition of rape. This necessitates an inquiry into the traditional sources of international law in international human rights law, IHL and international criminal law. Since the prohibition of rape and efforts to define the crime have been treated as two separate stages, a general study on its prohibition will often be the first issue explored in each regime, to be followed by the question of the definition. The objective is to display a holistic view of how the international community has dealt with the matter of sexual violence, with public international law as its medium, and to discern any level of consistency occurring between these separate domains of international law. In the process, variations in the general framework of the separate bodies of law will be highlighted for the purpose of illustrating reasons why different considerations may be taken into account when defining rape. A chapter has therefore been devoted to the common/dissimilar nature of rape committed within the context of armed conflict in relation to that carried out in times of peace. In doing so, the criminalisation of rape will serve the purpose of a study of the extent to which harmonisation exists between international human rights law, IHL and international criminal law and whether there is evidence of a shift towards a uniform and compulsory definition of rape in international law.