The integrative and complementary approach in the prevention of violent extremism and countering terrorism in the Western Balkans was applied in late 2015 at the EU level with the formal adoption of the “Council Conclusions on the Integrative and complemen tary approach to counter-terrorism and violent extremism in the Western Balkans”by the Justice and Home Affairs (JHA) Ministerial Council on 4 December 2015. As the implementation of the Western Balkan Counter-Terrorism Initiative (WBCTi) continued, the EU Member States supported the extension of this model approach to two other areas of internal security, namely border security and countering serious and organised crime. The concept of Integrative Internal Security Governance (IISG) in the Western Balkans was developed and formally introduced at the EU level with the adoption of the “ Council Conclusions on IISG” of 8 December 2016, also by the JHA Council of the EU and supported by the ministers of the Western Balkan Region at the EU–Western Balkans JHA Forum in December 2016. This document lays down the Terms of Reference related to the IISG implementation and the operation of the IISG supporting bodies. It is submitted to the members of the IISG Board for endorsement.