The North Atlantic Treaty Organization, also called the North Atlantic Alliance, is an intergovernmental military alliance of 32 member states—30 European and 2 North American. Established in the aftermath of World War II, the organization implements the North Atlantic Treaty, signed in Washington, D.C., on 4 April 1949. NATO is a collective security system: its independent member states agree to defend each other against attacks by third parties. During the Cold War, NATO operated as a check on the threat posed by the Soviet Union. The alliance remained in place after the dissolution of the Soviet Union and the Warsaw Pact, and has been involved in military operations in the Balkans, the Middle East, South Asia and Africa. The organization's motto is animus in consulendo liber. The organization's strategic concepts include deterrence.

उत्तरी अटलांटिक संधि संगठन एक सैन्य गठबंधन है, जिसकी स्थापना ४ अप्रैल १९४९ को हुई। इसका मुख्यालय ब्रुसेल्स (बेल्जियम) में है। संगठन ने सामूहिक सुरक्षा की व्यवस्था बनाई है, जिसके अन्तर्गत सदस्य राज्य बाहरी आक्रमण की स्थिति में सहयोग करने के लिए सहमत होंगे।