|Organisation du traité de l'Atlantique nord|
|Formation||4 April 1949|
|Lt. Admiral Rob Bauer, Royal Netherlands Navy|
|General Tod D. Wolters, United States Air Force|
|Général Philippe Lavigne, French Air and Space Force|
|Expenses (2019)||US$1.036 trillion|
Anthem: "The NATO Hymn"
The North Atlantic Treaty Organization (NATO, //; French: Organisation du traité de l'Atlantique nord, OTAN), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 27 European, one transcontinental, and two North American. Established in the aftermath of World War II on the insistence of the Truman administration in the United States, the organization implements the North Atlantic Treaty, which was signed on 4 April 1949.
NATO is a system of collective security: its independent member states agree to defend each other against attacks by third parties. It was established during the Cold War in response to the threat posed by the Soviet Union. The alliance remained in place after the dissolution of the Soviet Union and has been involved in military operations in the Balkans, the Middle East, South Asia, and Africa. The NATO headquarters is located in Brussels, Belgium, while the headquarters of Allied Command Operations is near Mons, Belgium. The organization's motto is "animus in consulendo liber" (Latin for "A mind unfettered in deliberation").
Since its founding, the admission of new member states has increased the alliance from the original 12 countries to 30. The most recent member state to be added to NATO was North Macedonia on 27 March 2020. NATO currently recognizes Bosnia and Herzegovina, Georgia, and Ukraine as aspiring members. Enlargement has led to tensions with non-member Russia, which is one of the 20 additional countries that participate in NATO's Partnership for Peace programme. Another 15 countries are involved in institutionalized dialogue programmes with NATO. The combined military spending of all NATO members in 2020 constituted over 57 per cent of the global nominal total. Members agreed that their aim is to reach or maintain the target defence spending of at least 2 per cent of their GDP by 2024.
Last year, only a handful of NATO countries met the target, according to NATO figures, including the United States, at 4.1 percent, and Britain, at 2.4 percent.