This sub-project aims to advance a whole-of-society approach to accountability for international crimes in Ukraine by strengthening the capacities of Ukrainian justice sector stakeholders, legal practitioners, policymakers, and societal actors in line with international and European standards. It combines targeted legal capacity development, policy support, and international cooperation to address both immediate accountability needs and longer-term institutional resilience. In order to improve the practical and theoretical knowledge of national legal actors on international criminal law (ICL) and international humanitarian law, the T.M.C. Asser Instituut is developing and delivering specialized training and knowledge-sharing tools for the Judiciary and defence lawyers, providing support for the handling of complex international crimes cases, and providing targeted expertise on emerging accountability challenges, such as the pillaging and illegal exploitation of natural resources in armed conflict. By investing in both current practitioners and future legal professionals, the sub-project promotes sustainability and coherence in Ukraine’s international crimes practice. In order to increase the understanding of transitional justice (TJ) mechanisms and processes, T.M.C. Asser is rolling out a comprehensive training programme to civil servants; convening policy round tables to facilitate engagement between Government entities, TJ bodies, international experts and civil society; and developing relevant policy briefs and legal analyses to reflect Ukraine’s priorities in this area. Finally, in order to strengthen cooperation on ICL matters, including through increased awareness and implementation of instruments of mutual legal assistance, T.M.C. Asser is enhancing the capacity of legal actors and policymakers through the development of tailored legal materials to improve implementation of treaties and European Union legal frameworks on judicial cooperation in criminal matters and through an exchange meeting between Ukrainian and Dutch policymakers and legal experts.