NATO (North Atlantic Treaty Organization) is an international military alliance consisting of 31 member states from Europe and North America. NATO was created by 12 countries from Europe and North America on April 4, 1949, and since then, 19 more countries have joined NATO through nine rounds of enlargement (in 1952, 1955, 1982, 1999, 2004, 2009, 2017, 2020, and 2023). Membership is open to any "European State in a position to further the principles of this Treaty and to contribute to the security of the North Atlantic area". Any decision to invite a country to join the Alliance is taken by the North Atlantic Council, NATOs principal political decision-making body, on the basis of consensus among all Allies.

Here is a list of all NATO member countries as of October 2023:

• Albania
• Belgium
• Bulgaria
• Canada
• Croatia
• Czech Republic
• Denmark
• Estonia
• France
• Germany
• Greece
• Hungary
• Iceland
• Italy
• Latvia
• Lithuania
• Luxembourg
• Montenegro
• Netherlands
• North Macedonia
• Norway
• Poland
• Portugal
• Romania
• Slovakia
• Slovenia
• Spain
• Turkey
• United Kingdom
• United States

It is worth noting that 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).