- International organisations in which full legal membership is officially solely open to states and the decision-making authority lies with representatives from governments. Intergovernmental organisations are considered as one of the main actors who play a regular part in global politics.
- Baylis, Smith & Owens 2013
- Willetts 2013
- Katsiadakis Helen (AA)
- Mergoupi-Savaidou Eirini (AA)