In this joint policy submission, FIDH, REDRESS and ECCHR call on States to prioritise victims’ rights in negotiations for a new multilateral treaty on international cooperation in the domestic prosecution of serious international crimes, including genocide, war crimes, and crimes against humanity. Since 2011, a group of States has advocated for a new multilateral treaty to enhance cooperation between States in investigations and prosecutions of serious international crimes. This Mutual Legal Assistance (MLA) Initiative is currently supported by over 70 countries.