The initiatives and efforts of the UN and the international community combatting ‘conflict-related sexual violence’ (CRSV) have increased and expanded through new approaches and frameworks in the last decades, through a development of terminology, definitions, forms of reporting, programming, sanctions, case law and international standards to bring perpetrators to justice and combat impunity. Sexual violence continues at high rates in the aftermath of many conflicts but has received much less international attention than wartime sexual violence. This article examines remaining international normative and accountability gaps for post-conflict sexual violence analysing the shortcomings in the interplay between international humanitarian law, human rights law and international criminal law in this context and by revisiting the Fundamental Standards of Humanity. The author also examines the new concept of CRSV in relation to international legal accountability, the boundaries of the definition on ‘crimes against humanity’ under the ICC Statute for sexual violence committed by non-state actors in post-conflict settings. The author concludes by claiming Meron’s ‘legal gap’ is found to be widely entrenched for these crimes of sexual violence.