Montenegro becomes the 29th member of the NATO.

The North Atlantic Treaty Organization (NATO, ; French: Organisation du trait de l'Atlantique nord, OTAN), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states 28 European and two North American. Established in the aftermath of World War II, the organization implements the North Atlantic Treaty, which was signed in Washington, D.C. 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. During the Cold War, NATO operated as a check on the perceived 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.

NATO's main headquarters are located in Brussels, Belgium, while NATO's military headquarters are near Mons, Belgium. The alliance has targeted deployments of their NATO Response Force in Eastern Europe, and the combined militaries of all NATO members include around 3.5 million soldiers and personnel. Their combined military spending as of 2020 constituted over 57 percent of the global nominal total. Members have agreed that their aim is to reach or maintain the target defence spending of at least two percent of their GDP by 2024.NATO formed with twelve founding members, and has added new members eight times, most recently when North Macedonia joined the alliance in March 2020. NATO currently recognizes Bosnia and Herzegovina, Georgia, and Ukraine as aspiring members, and is in talks with Finland and Sweden regarding their applications for membership. Enlargement has led to tensions with non-member Russia, which is one of the twenty additional countries that participate in NATO's Partnership for Peace programme. Another nineteen countries are involved in institutionalized dialogue programmes with NATO.

Montenegro ( (listen); Montenegrin: Crna Gora, Црна Гора, lit. 'Black Mountain', pronounced [tsr̩̂ːnaː ɡǒra]; Albanian: Mali i Zi) is a country in Southeastern Europe. It is located on the Adriatic Sea and is a part of the Balkans, sharing borders with Serbia to the northeast, Bosnia and Herzegovina to the north and west, Kosovo to the east, Albania to the southeast, the Adriatic Sea and Croatia to the southwest, and a maritime boundary with Italy. Podgorica, the capital and largest city, covers 10.4% of Montenegro's territory of 13,812 square kilometres (5,333 sq mi), and is home to roughly 30% of its total population of 621,000.During the Early Medieval period, three principalities were located on the territory of modern-day Montenegro: Duklja, roughly corresponding to the southern half; Travunia, the west; and Rascia proper, the north. The Principality of Zeta emerged in the 14th and 15th centuries. From the late 14th century to the late 18th century, large parts of southern Montenegro were ruled by the Venetian Republic and incorporated into Venetian Albania. The name Montenegro was first used to refer to the country in the late 15th century. After falling under Ottoman rule, Montenegro regained its independence in 1696 under the rule of the House of Petrović-Njegoš, first as a theocracy and later as a secular principality. Montenegro's independence was recognised by the Great Powers at the Congress of Berlin in 1878. In 1910, the country became a kingdom.

After World War I, the kingdom became part of Yugoslavia. Following the breakup of Yugoslavia, the republics of Serbia and Montenegro together proclaimed a federation. Following an independence referendum held in May 2006, Montenegro declared its independence and the confederation peaceably dissolved.Montenegro has an upper-middle-income economy and ranks 48th in the Human Development Index. It is a member of the United Nations, NATO, the World Trade Organization, the Organization for Security and Co-operation in Europe, the Council of Europe, and the Central European Free Trade Agreement. Montenegro is also a founding member of the Union for the Mediterranean, and is currently in the process of joining the European Union.