United Nations peacekeeping is the deployment of international military, police, and civilian personnel under United Nations command to help countries transition from conflict to peace. Authorized by the United Nations Security Council and administered by the Department of Peace Operations, it is one of the principal instruments through which the United Nations addresses threats to international peace and security. It is distinguished from peacemaking, peace enforcement, and peacebuilding, although these activities may overlap in practice.
Peacekeeping is not mentioned in the United Nations Charter; it developed during the Cold War as an improvised response to crises the Security Council was unable to address through the originally planned collective security provisions. Peacekeeping is governed by three principles: there must be consent of the parties, impartiality, and non-use of force except in self-defense and defense of the mandate. The mandates of UN peacekeeping missions have expanded significantly over time, from early observer deployments to multidimensional operations which may support complex peace agreements or protect civilians in active conflicts under Chapter VII of the UN Charter. Peacekeepers may include soldiers, police, and civilian participants; they wear their home countries' uniforms and Blue Helmets or Blue Berets, which have become synonymous with UN peacekeeping.
Since 1948, more than two million people from 125 countries have served in 72 UN peacekeeping operations; the forces were collectively awarded the Nobel Peace Prize in 1988. As of 2026, eleven operations are active, with a combined budget of $5.66 billion and around 53,000 personnel deployed from 117 countries, the largest contributors being Nepal, Rwanda, Bangladesh, India, and Pakistan. Scholars have found that peacekeeping is associated with reduced conflict recurrence and fewer civilian casualties, although effectiveness varies with the local situation and a mission's mandate.
The current head of the Department of Peace Operations is Jean-Pierre Lacroix, who has held the office since 1 April 2017.
Conceptual foundations
Non-charter origins The UN Charter makes no reference to peacekeeping. Its framers envisioned a collective security system in which the Security Council, supported by armed forces made available by member states under Article 43 and coordinated through the Military Staff Committee established under Article 47, would respond directly to threats to international peace and security. However, this system never functioned as designed due to disagreements between the two sides of the beginning Cold War. Peacekeeping subsequently developed as an improvised institutional response to crises which the Security Council wanted to address despite the failure of the original mechanisms.
Because peacekeeping had no Charter basis, UN Secretary-General Dag Hammarskjöld described it as a "Chapter Six and a Half" activity, situated between the peaceful dispute settlement mandated under Chapter VI, and the military measures authorized under Chapter VII. The phrase has remained the standard shorthand for peacekeeping's legal and operational position, and its emergence from the necessity of working around the Charter's practical limits.
Core principles UN peacekeeping follows three core principles, first articulated by Hammarskjöld in 1958 and subsequently codified in the 2008 UN Peacekeeping Operations: Principles and Guidelines, commonly known as the Capstone Doctrine. These principles are:
Peacekeepers must be deployed with the consent of the parties to the conflict, who must be committed to a political process. Without such consent, an operation risks becoming a party to the conflict and being drawn toward enforcement action. Peacekeepers must exhibit impartiality, implementing their mandate without favour or prejudice to any party. Impartiality is not equivalent to neutrality: a peacekeeping operation may penalize infractions of the peace process while remaining impartial in its dealings with the parties. Peacekeepers must not use force except in self-defense, and in defense of the mandate. They are generally not an offensive force, but are allowed to proactively deter forceful attempts to disrupt their mandate in what is called "robust peacekeeping".
The three principles are interdependent and have been stretched (particularly the third) by the demands of post-Cold War deployments. The Security Council, even when authorizing robust mandates under Chapter VII, regularly reaffirms them in operative paragraphs of mission resolutions.
Distinction from other activities Peacekeeping is distinguished from three related activities: Peacemaking refers to diplomatic efforts to bring hostile parties to a negotiated agreement, typically through mediation or arbitration under Chapter VI of the Charter. Peace enforcement refers to the use of coercive measures, including military force, to restore international peace and security under Chapter VII; it does not require the consent of the parties and is generally undertaken by member-state coalitions or regional organisations authorized by the Security Council, rather than by UN-commanded forces. Peacebuilding refers to longer-term efforts to address the structural causes of conflict and to consolidate peace, including support for institutions and economic recovery. The UN acknowledges that these activities are mutually reinforcing and that contemporary peacekeeping operations frequently incorporate aspects of these other processes.
Ongoing missions
Acronym Name Country/regionStart year 2025–26 budget Ref MINURSO Mission for the Referendum in Western Sahara 1991 $71M MINUSCA Stabilization Mission in the Central African Republic 2014 $1170M MONUSCO Stabilization Mission in the Congo 2010 $870M UNDOF Disengagement Observer Force / 1974 $70M UNFICYP Peacekeeping Force in Cyprus 1964 $57M UNIFIL Interim Force in Lebanon / 1978 $550M UNISFA Interim Security Force for Abyei / 2011 $310M UNMIK Interim Administration Mission in Kosovo 1999 $46M UNMISS Mission in South Sudan 2011 $1190M UNMOGIP Military Observer Group in India and Pakistan / 1951 $9M UNTSO Truce Supervision Organization Middle East1948 $42M
History Scholars commonly divide the history of UN peacekeeping into three "generations" of traditional, multidimensional, and robust peacekeeping, each of which have distinct mandates and practices. However, these are not formal UN classifications, and the periods have some overlap in practice.
Traditional peacekeeping (1948–1988) The first peacekeeping mission was initiated as the UN Truce Supervision Organization (UNTSO), which was designed to oversee a ceasefire between the warring parties in the 1948 Arab–Israeli War. UNTSO remains operative more than 75 years after its creation. In 1951, the UN Military Observer Group in India and Pakistan (UNMOGIP) was authorized to monitor relations between the two nations after the partition of India in 1947 as a result of decolonization.
Both UNTSO and UNMOGIP were small, unarmed observer missions. This evolved into armed, interpositional peacekeeping during the 1956 Suez Crisis, after France and the United Kingdom vetoed Security Council action against the Anglo-French-Israeli intervention in Egypt. In response, the General Assembly invoked the 1950 "Uniting for Peace" resolution and requested Secretary-General Dag Hammarskjöld to present a plan for a peacekeeping force. Hammarskjöld drew on a proposal of Canadian Secretary of State for External Affairs Lester Bowles Pearson, who had initially suggested a peacekeeping force of mainly Canadian peacekeepers. However, Egypt did not believe a Commonwealth nation's troops would be sufficiently neutral, and Hammarskjöld thus designed the multi-national UN Emergency Force (UNEF). UNEF supervised troop withdrawals and remained as a buffer between Egyptian and Israeli forces until 1967. Pearson won the Nobel Peace Prize in 1957 for his work.
Subsequent first-generation operations followed the UNEF template: small, lightly armed missions which acted as observers and buffers, staffed predominantly by non-aligned or middle-power states, operated with the consent of the host state, and used force only in self-defense. Notable examples include the UN Operation in the Congo (ONUC, 1960–1964), the UN Peacekeeping Force in Cyprus (UNFICYP, 1964–present), and the UN Disengagement Observer Force (UNDOF) on the Golan Heights (1974–present). ONUC was the most ambitious of these missions and at points strained the conventional bounds of traditional peacekeeping, deploying significant force against Katangese secessionists; Hammarskjöld died in a plane crash in September 1961 while travelling to negotiate a ceasefire with the Katangese leadership.
In 1988, the Nobel Peace Prize was awarded collectively to the UN peacekeeping forces. The Norwegian Nobel Committee stated that the forces "represent the manifest will of the community of nations" and had "made a decisive contribution" to the resolution of conflict around the world. By that point thirteen operations had been authorized; another five would be approved in 1988–1989 alone, marking the beginning of a sharp expansion in UN peacekeeping activity.
Multidimensional peacekeeping (1988–1999)
The end of the Cold War transformed UN peacekeeping. With the Security Council no longer paralyzed by superpower rivalry, larger and more complex missions were established, often to implement comprehensive peace agreements in intrastate conflicts and civil wars. Mandates expanded beyond ceasefire monitoring to include disarmament, demobilization and reintegration of combatants, electoral assistance, human rights monitoring, security sector reform, and in some cases transitional administration of territory. Secretary-General Boutros Boutros-Ghali's 1992 report An Agenda for Peace codified the transition, distinguishing peacekeeping from other activities, and arguing that the boundaries between them were becoming porous. The Department of Peacekeeping Operations (DPKO) was established in 1992 to manage this expanded portfolio.
Several missions of this period are widely regarded as successful, including the UN Transition Assistance Group (UNTAG), which supervised Namibian independence in 1989–1990; the UN Observer Mission in El Salvador (ONUSAL), which supported implementation of the Chapultepec Peace Accords from 1991; and the UN Operation in Mozambique (ONUMOZ), which oversaw the transition from civil war to multiparty elections in 1992–1994. The UN Transitional Authority in Cambodia (UNTAC, 1992–1993), one of the largest operations of the era, organized elections and supervised a partial demobilisation despite the non-cooperation of the Khmer Rouge.
Other deployments failed catastrophically, often where missions had been dispatched without secured ceasefires or the consent of all parties. In Somalia, the UN Operation in Somalia II (UNOSOM II) became drawn into combat with local militias following the collapse of state authority. In Rwanda, the UN Assistance Mission for Rwanda (UNAMIR) lacked the troop strength and political backing to prevent the 1994 Rwandan genocide, in which over 800,000 people were killed. In the Yugoslav Wars, the UN Protection Force (UNPROFOR) was deployed in conditions where "there was no peace to keep"; in July 1995, Bosnian Serb forces committed the Srebrenica massacre in a UN-designated "safe area" despite the presence of a Dutch UNPROFOR battalion. These failures led to a re-examining of the three original peacekeeping principles and their applicability to contemporary crises.