The United Nations System is a complex network of intergovernmental organizations, agencies, funds, and programmes, not a single act or institution. It is a concept that encompasses the United Nations itself and the many autonomous entities that cooperate with it. The system's origin is the establishment of the United Nations on October 24, 1945, after the UN Charter was ratified by a majority of signatories, including the five permanent members of the Security Council. It was created to prevent another world war and to maintain international peace and security, following the destruction of World War II.
The system works through the UN Charter, which established six principal organs: the General Assembly, the Security Council, the Economic and Social Council (ECOSOC), the Trusteeship Council (which suspended operations in 1994), the International Court of Justice (ICJ), and the Secretariat. The Security Council is unique as it can make decisions that member states are legally obligated to implement, while the General Assembly's resolutions are generally recommendations. The UN System connects to numerous related institutions, including 15 specialized agencies like the World Health Organization (WHO) and the Food and Agriculture Organization (FAO), which are legally independent but linked to the UN through agreements. It also includes funds and programmes like the United Nations Development Programme (UNDP) and the United Nations Children's Fund (UNICEF).
The system is currently undergoing significant change under the UN80 Initiative, a system-wide reform effort launched by the Secretary-General to make the UN more effective and coherent. Recent changes include the General Assembly's adoption of a resolution on April 1, 2026, to strengthen how UN mandates are created and reviewed. Furthermore, the General Assembly approved the merger of the United Nations System Staff College (UNSSC) into the United Nations Institute for Training and Research (UNITAR) to establish the United Nations Institute for Capability and Learning Innovation (UNICLI), which will be formally established on January 1, 2027. The core structure of the six principal organs, however, remains the foundation of the system.