The NATO Parliamentary Assembly (NATO PA) is an interparliamentary organisation that brings together parliamentarians from member countries of the North Atlantic Treaty Organization (NATO), as well as partner countries outside the Alliance, to discuss key political, security, and defence issues in the Euro-Atlantic region. The Assembly places a particular priority on strengthening transatlantic dialogue between members of national parliaments in North America and Europe.

The NATO PA was established on 18 July 1955 in Paris, when representatives from 14 member countries of the North Atlantic Treaty Organization convened for the Conference of Members of Parliament of NATO Countries. Over time, the title evolved, first becoming the NATO Parliamentarians Conference and later, in 1966, the North Atlantic Assembly. Since 1 June 1999, the organisation has officially been known as the NATO Parliamentary Assembly.

As the global security environment has been evolving, the role of the Assembly has grown significantly, alongside the growing importance of parliamentarians in reaching consensus on issues relevant to the Alliance, making responsible decisions, ensuring the transparency of the Alliance’s activities, strengthening parliamentary democracy, providing support to countries aspiring to NATO membership, and  cooperating with states that, while not seeking membership, are willing to work together with the Alliance.

The NATO PA is an independent organisation that operates separately from NATO. Nevertheless, the two organisations cooperate closely: NATO responds on all recommendations and resolutions adopted by the Assembly; the NATO Secretary General participates in the Assembly sessions and other key events; and a meeting with the North Atlantic Council is held annually.

In response to the fall of the Berlin Wall in late 1980s, the NATO PA broadened its mandate by developing close relations with political leaders in Central and East European countries. International relations with these countries were organised under the Rose-Roth programme, initiated in 1990 by the then President of the Assembly, U.S. Congressman Charlie Rose and U.S. Senator Bill Roth. The original aim of the Rose-Roth programme was to support partner countries in Central and Eastern Europe in navigating the challenging post-Cold War transition to democracy following the fall of the Berlin Wall, a process that involved complex political and economic reforms. 

The activities of the NATO PA are carried out according to the Rules of Procedure. Full members of the Assembly may be representatives of the national parliaments of NATO member countries. Members of governments cannot be delegated to the Assembly. The number of members in each delegation is set out in the Rules of Procedure and depends on the size and population of the country. Each country selects its delegation in accordance with the procedures established by its national Parliament, provided that the delegation is representative of the main political forces. Members of delegations may be supported by alternate members.

Currently, the Assembly comprises 281 parliamentarians from 32 NATO member countries, who have an exclusive right to vote on Assembly decisions.

In addition to delegates from NATO member countries, the Assembly’s activities also involve delegates from 11 associate countries, four Mediterranean associate countries, as well as seven parliamentary observer delegations, In total, approximately 370 parliamentarians participate in the Assembly's work.

In order to strengthen dialogue with the Middle East and North Africa region, the Assembly has established the Mediterranean and Middle East Special Group. The Ukraine-NATO Interparliamentary Council and the Georgia-NATO Interparliamentary Council are also part of the Assembly. The activities of the former NATO-Russia Parliamentary Committee were suspended in April 2014 following Russia’s military intervention in Ukraine.

The NATO Parliamentary Assembly holds two sessions each year, namely a Spring Session and an Annual Session in the autumn. Each year, the sessions are hosted by different countries. The Assembly may express its position through recommendations, resolutions, and reports.

The Assembly has five committees:

Political Committee;  

Defence and Security Committee;  

Economics and Security Committee;

Committee on Democracy and Security;

Science and Technology Committee.  

Eight sub-committees operate within the committees. Each committee organises several visits each year, targeting topics and regions that are most relevant to its mandate.

The Assembly is led by the Standing Committee, composed of the heads of each delegation, the President of the Assembly, the Vice-Presidents, the Treasurer, and the Secretary General of the Assembly.

The Assembly Bureau, consisting of the President, Vice-Presidents, and the Treasurer, addresses important matters concerning the Assembly when the Standing Committee is not in session. The President represents the Assembly and settles key issues when no meetings of the Assembly, the Standing Committee and the Bureau are taking place.

The International Secretariat of the NATO PA is based in Brussels and headed by the Secretary General, who is appointed and dismissed by the Standing Committee.

The official languages of the Assembly are English and French.                                                 

The activities of the Assembly are financed through contributions from member countries.