​The NATO Parliamentary Assembly (NATO-PA), originally called the North Atlantic Assembly (NAA), is an inter-parliamentary organization founded in 1955 in order to enable representatives of the parliaments of members of NATO to meet and discuss common security problems.

Today it includes representatives of the legislative bodies of the 29 members of NATO as well as of 12 associated countries, of 4 Mediterranean associated countries and of observers from 8 other countries. Inter-parliamentary assemblies such as the OSCE Parliamentary Assembly, the Parliamentary Assembly of the Council of Europe as well as the European Parliament also send delegations.

The NATO-PA comprises 266 delegates from the member states. The total number of delegates taking part in the activities of the Assembly is approximately 360. Most of these parliamentarians are members of defence committees in their own countries. The chairmen and deputy chairmen of the Swiss Committees on Security Policy thus have the opportunity to meet their counterparts when they attend NATO-PA functions.

From a legal point of view, the NATO-PA and NATO are independent entities. The absence of a formal link with NATO has not prevented the Assembly from developing close working relations with it over the years, however. The Assembly has only advisory powers, but over time it has taken on a role as an important forum for discussing security.

The Assembly is funded directly by the parliaments and governments of its member states; at a financial and administrative level it is independent of NATO itself. The Assembly’s international secretariat is based in Brussels.