The NEA has a long tradition of expertise in the area of nuclear emergency policy, planning, preparedness and management. Through its activities in this field, it offers member countries unbiased assistance on nuclear preparedness matters, with a view to facilitating improvements in nuclear emergency preparedness strategies and response at the international level. A central approach to this has been the preparation and conduct of the International Nuclear Emergency Exercise (INEX) series. The Fifth International Nuclear Emergency Exercise (INEX-5) was developed specifically in response to member countries' desire to test and demonstrate the value of changes put in place following the Fukushima Daiichi nuclear power plant accident. Exercise objectives focused on notification, communication and interfaces related to catastrophic events involving ionising radiation and/or radioactive material. The exercise was held during 2015 and 2016, with 22 countries participating in the exercise. This report summarises the major evaluation outcomes of the national and regional exercises, policy level outcomes, recommendations and follow-up activities emerging from INEX-5 and the discussions at the INEX-5 International Workshop. A set of key needs were identified in areas such as real-time communication and information sharing among countries and international partners, improving cross-border and international co-ordination of protective measures and considering the mental health impacts on populations when implementing protective measures.