The International Court of Justice (ICJ; French: Cour internationale de justice, CIJ), or colloquially the World Court, is the principal judicial organ of the United Nations (UN). It settles legal disputes submitted to it by states and provides advisory opinions on legal questions referred to it by other UN organs and specialized agencies. The ICJ is the only international court that adjudicates general disputes between countries, with its rulings and opinions serving as primary sources of international law. It is one of the six principal organs of the United Nations.
Established in June 1945 by the Charter of the United Nations, the court began work in April 1946. It is the successor to the Permanent Court of International Justice (PCIJ), which was established by the League of Nations in 1920. Its founding statute is an integral part of the UN Charter and draws heavily from that of its predecessor. All UN member states are automatically parties to the ICJ Statute. However, the court's jurisdiction in contentious cases is founded upon the consent of the states party to a dispute, which may be given through special agreements or declarations accepting the court's compulsory jurisdiction.
The court is composed of a panel of 15 judges elected by the UN General Assembly and Security Council for nine-year terms. The composition of the bench is required to represent the "main forms of civilization and the principal legal systems of the world," and no two judges may be nationals of the same country. The ICJ is seated in the Peace Palace in The Hague, Netherlands, making it the only principal UN organ not located in New York City. Its official working languages are English and French.
Since its first case was submitted in 1947, the court has entertained 201 cases as of September 2025. While its judgments are binding on the parties and final, the ICJ possesses no formal enforcement mechanism. Enforcement of its rulings is ultimately a political matter for the UN Security Council, where it is subject to the veto power of the five permanent members.
The first permanent institution established for the purpose of settling international disputes was the Permanent Court of Arbitration (PCA), which was created by the Hague Peace Conference of 1899. Initiated by the Russian Tsar Nicholas II, the conference involved all the world's major powers, as well as several smaller states, and resulted in the first multilateral treaties concerned with the conduct of warfare. Among these was the Convention for the Pacific Settlement of International Disputes, which set forth the institutional and procedural framework for arbitral proceedings, which would take place in The Hague, Netherlands. Although the proceedings would be supported by a permanent bureau—whose functions would be equivalent to that of a secretariat or court registry—the arbitrators would be appointed by the disputing states from a larger pool provided by each member of the convention. The PCA was established in 1900 and began proceedings in 1902.
A second Hague Peace Conference in 1907, which involved most of the world's sovereign states, revised the convention and enhanced the rules governing arbitral proceedings before the PCA. During this conference, the United States, Great Britain and Germany submitted a joint proposal for a permanent court whose judges would serve full-time. As the delegates could not agree how the judges would be selected, the matter was shelved pending an agreement to be adopted at a later convention.
The Hague Peace Conferences, and the ideas that emerged therefrom, influenced the creation of the Central American Court of Justice, which was established in 1908 as one of the earliest regional judicial bodies. Various plans and proposals were made between 1911 and 1919 for the establishment of an international judicial tribunal, which would not be realized in the formation of a new international system following the First World War.
The Permanent Court of International Justice
The unprecedented bloodshed of the First World War led to the creation of the League of Nations, established by the Paris Peace Conference of 1919 as the first worldwide intergovernmental organization aimed at maintaining peace and collective security. Article 14 of the League of Nations Covenant called for the establishment of a Permanent Court of International Justice (PCIJ), which would be responsible for adjudicating any international dispute submitted to it by the contesting parties, as well as to provide an advisory opinion upon any dispute or question referred to it by the League of Nations.
In December 1920, following several drafts and debates, the Assembly of the league unanimously adopted the statute of the PCIJ, which was signed and ratified the following year by a majority of members. Among other things, the new statute resolved the contentious issues of selecting judges by providing that the judges be elected by both the council and the Assembly of the league concurrently but independently. The makeup of the PCIJ would reflect the "main forms of civilization and the principal legal systems of the world". The PCIJ would be permanently placed at the Peace Palace in The Hague, alongside the Permanent Court of Arbitration.
The PCIJ represented a major innovation in international jurisprudence in several ways:
Unlike previous international arbitral tribunals, it was a permanent body governed by its statutory provisions and rules of procedure
It had a permanent registry that served as a liaison with governments and international bodies
Its proceedings were largely public, including pleadings, oral arguments, and all documentary evidence
It was accessible to all states and could be declared by states to have compulsory jurisdiction over disputes
The PCIJ Statute was the first to list sources of law it would draw upon, which in turn became sources of international law
Judges were more representative of the world and its legal systems than any prior international judicial body
Unlike the ICJ, the PCIJ was not part of the league, nor were members of the league automatically a party to its statute. The United States, which played a key role in both the second Hague Peace Conference and the Paris Peace Conference, was notably not a member of the league. However, several of its nationals served as judges of the court.