The Institute of Security and Global Affairs (ISGA) is a scientific institute that specialises in security issues. The ISGA is a part of the Faculty of Governance and Global Affairs at Leiden University. The ISGA has developed from the Centre for Terrorism and Counterterrorism (CTC) and the Centre for Global Affairs.

Researchers at this institute are engaged in interdisciplinary research and teaching within the international scientific field of security studies. The approach to issues of security is glocal, that is to say that the local, national, transnational and global impact are studied and analysed in conjunction with each other.

This teaching and research takes place in the city of The Hague, the centre of government and the third largest city in the Netherlands, but also the International City of Peace, Justice and Security. Given the prominent position of The Hague, there is an inspiring interaction between this academic institute and other knowledge institutions, national and international governments, the private sector and NGOs.