The North Atlantic Treaty Organization (NATO) is an international military alliance consisting of 32 member states from Europe and North America. It was established at the signing of the North Atlantic Treaty on 4 April 1949. Of the 32 member countries, 30 are in Europe and 2 are in North America. Between 1994 and 1997, wider forums for regional cooperation between NATO and its neighbours were set up, including the Partnership for Peace, the Mediterranean Dialogue initiative, and the Euro-Atlantic Partnership Council. The majority of NATO members are also member states of the European Union.
All members have militaries, except for Iceland, which does not have a typical army (but it does have a coast guard and a small unit of civilian specialists for NATO operations). Three of NATO's members are nuclear weapons states: France, the United Kingdom, and the United States. NATO has 12 original founding member states. Three more members joined between 1952 and 1955, and a fourth (Spain) joined in 1982. Since the end of the Cold War, NATO has added 16 more members from 1999 to 2024. Article 5 of the treaty states that if an armed attack occurs against one of the member states, it shall be considered an attack against all members, and other members shall assist the attacked member, with armed forces if necessary. Article 6 of the treaty limits the scope of Article 5 to the islands north of the Tropic of Cancer, the North American and European mainlands, the entirety of Turkey, and French Algeria, the last of which has been moot since July 1962. Thus, an attack on Hawaii, Puerto Rico, French Guiana, the Falkland Islands, Ceuta or Melilla, among other places, would not trigger an Article 5 response.
NATO recognizes Bosnia and Herzegovina, Georgia, and Ukraine as aspiring members as part of their Open Door enlargement policy.
Founding members and enlargement
NATO was established on 4 April 1949 via the signing of the North Atlantic Treaty (Washington Treaty). The 12 founding members of the Alliance were: Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom, and the United States.
The various allies all signed the Ottawa Agreement, which is a 1951 document that acts to embody civilian oversight of the Alliance.
Current membership consists of 32 countries. In addition to the 12 founding countries, four new members joined during the Cold War: Greece and Turkey (1952), West Germany (1955) and Spain (1982). Additionally, NATO experienced territorial expansion during this period without adding new member states when Zone A of the Free Territory of Trieste was annexed by Italy in 1954, and the territory of the former East Germany was added with the reunification of Germany in 1990. NATO further expanded after the Cold War, adding the Czech Republic, Hungary, and Poland (1999); Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, and Slovenia (2004); Albania and Croatia (2009); Montenegro (2017); North Macedonia (2020); Finland (2023); and Sweden (2024). Of the territories and members added between 1990 and 2024, all except for Finland and Sweden were either formerly part of the Warsaw Pact (including the formerly Soviet Baltic states) or territories of the former Yugoslavia. No countries have left NATO since its founding, although France withdrew from NATO unified command between 1966 and 2009.
Since the accession of Sweden on 7 March 2024, the North Atlantic Treaty Organization covers a total area of .
List of member states
The current members and their dates of admission are listed below. + Flag Map Name Capital Largest city Accession Population Area Military budgetas % GDP 2024 GDP 2025(million US$) Languages Albania Tirana 2,854,710 2.0328,372 Albanian Belgium City of Brussels Brussels Capital Region 11,611,419 1.30684,864 Dutch French German BulgariaSofia 6,885,868 2.18117,007 Bulgarian Canada Ottawa Toronto 38,155,012 1.372,225,341 English French Croatia Zagreb 4,060,135 1.8198,951 Croatian Czech Republic Prague 10,510,751 2.10360,244 Czech Denmark Copenhagen 5,854,240 2.37449,940 Danish Estonia Tallinn 1,328,701 3.4345,004 Estonian Finland Helsinki 5,619,399 2.41303,945 Finnish SwedishFranceParis64,531,4442.063,211,292French Germany Berlin 83,408,554 2.124,744,804 German Greece Athens 10,445,365 3.08267,348 Greek HungaryBudapest 9,709,786 2.11237,070 Hungarian Iceland Reykjavík 370,335 0.035,309 Icelandic Italy Rome 59,240,329 1.492,422,855 Italian Latvia Riga 1,873,919 3.1543,598 Latvian Lithuania Vilnius 2,786,651 2.8589,192 Lithuanian Luxembourg Luxembourg 639,321 1.2996,613 Luxembourgish French German Montenegro Podgorica 627,859 2.028,562 Montenegrin Netherlands Amsterdam 17,501,696 2.051,272,011 Dutch North Macedonia Skopje 2,103,330 2.2217,885 Macedonian Norway Oslo 5,403,021 2.20504,276 Norwegian Poland Warsaw 38,307,726 4.12979,960 Polish Portugal Lisbon 10,290,103 1.55321,440 Portuguese Romania Bucharest 19,328,560 2.25403,395 Romanian Slovakia Bratislava 5,447,622 2.0147,031 Slovak Slovenia Ljubljana 2,119,410 1.2975,224 Slovene Spain Madrid 47,486,935 1.281,799,511 Spanish Sweden Stockholm 10,467,097 2.14620,297 Swedish Turkey Ankara Istanbul 84,775,404 2.091,437,406 Turkish United Kingdom London 67,281,039 2.333,839,180 English United States Washington, D.C. New York City 336,997,624 3.3830,507,217
Special arrangements The three Nordic countries which joined NATO as founding members, Denmark, Iceland and Norway, chose to limit their participation in three areas: there would be no permanent peacetime bases, no nuclear warheads and no Allied military activity (unless invited) permitted on their territory. However, Denmark allowed the US to maintain an existing base, Thule Air Base (now Pituffik Space Base), in Greenland.
From the mid-1960s to the mid-1990s, France pursued a military strategy of independence from NATO under a policy dubbed "Gaullo-Mitterrandism". Nicolas Sarkozy negotiated the return of France to the integrated military command and the Defence Planning Committee in 2009, the latter being disbanded the following year. France remains the only NATO member outside the Nuclear Planning Group and unlike the United States and the United Kingdom, will not commit its nuclear-armed submarines to the alliance.
Membership aspirations , three additional states have formally informed NATO of their membership aspirations: Bosnia and Herzegovina, Georgia, and Ukraine. NATO members agreed at the 2008 Bucharest Summit that Georgia and Ukraine "will become members of NATO in the future". Bosnia and Herzegovina was invited by NATO to join the Membership Action Plan (MAP) in April 2010.
Withdrawal No state has ever withdrawn from NATO, but some dependencies of member states have not requested membership after becoming independent: (independence from the United Kingdom in 1960) (independence from France in 1962) (independence from the United Kingdom in 1964)
Military personnel The following list is constructed from The Military Balance, published annually by the International Institute for Strategic Studies.
+ Numbers of military personnelCountryActiveReserveParamilitaryTotalPer 1,000 capitatotal active
Military expenditures
The defence spending of the United States is more than double the defence spending of all other NATO members combined. (Note that this is total U.S. defense spending, not spending specifically for NATO) Criticism of the fact that many member states were not contributing their fair share in accordance with the international agreement by then US president Donald Trump caused various reactions from American and European political figures, ranging from ridicule to panic. While NATO members have committed to spending at least 2% of their Gross Domestic Product (GDP) on defence, most of them did not meet that goal in 2023.
Member state Population GDP(nominal)($billions) Defence expenditure (US$) Personnel Total($millions) % real GDP Per capita 2,872,849 29.89 598 2.00 157 6,600 12,055,794 725.00 14,465 2.00 1,085 22,100 6,670,476 128.97 2,755 2.14 317 26,600 40,086,114 2,282.50 45,562 2.00 1,051 70,900 4,026,339 104.04 2,182 2.10 453 13,600 10,745,564 388.03 7,819 2.01 574 29,100 5,936,566 458.55 15,299 3.34 2,416 18,000 1,301,740 47.42 1,623 3.42 909 7,800 5,712,138 316.95 9,095 2.87 1,49727,700 67,065,327 3,367.43 68,905 2.05 940 201,700 83,982,479 5,042.75 120,747 2.39 1,257 182,300 10,186,705 282.57 7,871 2.79 651 104,100 9,479,265 247.43 5,130 2.07 416 19,900 355,437 38.34 60,775,803 2,549.38 51,197 2.01 798 193,700 1,760,090 47.70 1,782 3.74 790 8,200 2,472,510 94.84 3,797 4.00 1.019 19,000 711,892 66.20 1,408 2.13 1.750 1,000 632,886 9.18 188 2.05 235 1,700 17,494,438 1,329.13 30,498 2.59 1,618 45,100 2,103,765 18.89 402 2.13 183 6,000 5,843,854 518.84 16,598 3.20 3,026 26,700 37,912,247 1031.96 44,360 4.30 891 252,900 9,927,058 345.50 6,911 2.00 546 21,500 18,362,627 420.57 9,300 2.21 361 69,800 5,482,699 153.63 3,162 2.06 480 13,500 2,097,913 79.55 1,624 2.04 637 5,900 46,141,946 1,897.02 37,940 2.00 691 117,400 10,603,412 663.33 16,601 2.50 1,53125,700 93,157,395 1,563.43 36,414 2.33 265 370,300 70,422,211 4,020.45 92,875 2.31 1,146 126,100 345,949,138 30,674.37 980,000 3.19 2,460 1,291,300 992,328,677 58,943.84 1,637,108 2.771,4343,326,200
Political and popular support
Pew Research Center's 2016 survey among its member states showed that while most countries viewed NATO positively, most NATO members preferred keeping their military spending the same. The response to whether their country should militarily aid another NATO country if it were to get into a serious military conflict with Russia was also mixed. Roughly half or fewer in six of the eight countries surveyed say their country should use military force if Russia attacks a neighboring country that is a NATO ally. And at least half in three of the eight NATO countries say that their government should not use military force in such circumstances. The strongest opposition to responding with armed force is in Germany (58%), followed by France (53%) and Italy (51%). More than half of Americans (56%) and Canadians (53%) are willing to respond to Russian military aggression against a fellow NATO country. A plurality of the British (49%) and Poles (48%) would also live up to their Article 5 commitment. The Spanish are divided on the issue: 48% support it, 47% oppose.
YouGov, a market research company that is mainly active in the UK also hosts a regularly updated public opinion polling for NATO. As of 6 January 2025, 45% of UK citizens strongly support NATO, 31% Tend to support NATO, 18% Don't know, 3% Tend to oppose and 3% Strongly oppose. Older people (65+) Strongly support NATO at 59%, whilst in younger demographics (18-24), Tend to support ranks the highest at 34%, and Don't know is at 33%.
A 2025 poll found that support for NATO membership was 52%, compared to the 66% of Slovenians who voted for NATO membership in a referendum in 2003.
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