The United Nations Security Council (UNSC) is one of the six principal organs of the United Nations (UN) and is charged with ensuring international peace and security, recommending the admission of new UN members to the General Assembly, and approving any changes to the UN Charter. Its powers include establishing peacekeeping operations, enacting international sanctions, and authorizing military action. The UNSC is the only UN body with the authority to issue binding resolutions on member states.

Like the UN as a whole, the Security Council was created after World War II to address the failings of the League of Nations in maintaining world peace. It held its first session on 17 January 1946 but was largely paralyzed in the following decades by the Cold War between the United States and the Soviet Union (and their allies). Nevertheless, it authorized military interventions in the Korean War and the Congo Crisis and peacekeeping missions in Cyprus, West New Guinea, and the Sinai Peninsula. With the collapse of the Soviet Union, UN peacekeeping efforts increased dramatically in scale, with the Security Council authorizing major military and peacekeeping missions in Kuwait, Namibia, Cambodia, Bosnia and Herzegovina, Rwanda, Somalia, Sudan, and the Democratic Republic of the Congo.

The Security Council consists of fifteen members, of which five are permanent: China, France, Russia, the United Kingdom, and the United States. These were the great powers that were the victors of World War II (or their successor states). Permanent members can veto (block) any substantive Security Council resolution, including those on the admission of new member states to the United Nations or nominees for the office of Secretary-General. This veto right does not carry over into any General Assembly or emergency special sessions of the General Assembly matters or votes. The other ten members are elected on a regional basis for a term of two years. The body's presidency rotates monthly among its members.

Resolutions of the Security Council are typically enforced by UN peacekeepers, which consist of military forces voluntarily provided by member states and funded independently of the main UN budget. As of November 2021, there have been 12 peacekeeping missions with over 87,000 personnel from 121 countries, with a total budget of approximately $6.3 billion.