ICJ vs ICC: What the Two Courts Do, Who They Hear and How They Differ
ICC headquarters in The Hague, photographed in 2019. Photo: OSeveno / Wikimedia Commons, CC BY-SA 3.0.
The ICJ vs ICC question comes down to the subject and legal route. The International Court of Justice (ICJ) settles legal disputes between states and gives advisory opinions, while the International Criminal Court (ICC) investigates and, where warranted, tries individuals for four crimes under the Rome Statute. Both courts sit in The Hague, but each has its own legal foundation, parties and procedure. A single crisis can raise a state-to-state legal question and a separate question about individual criminal responsibility.
Key facts about the ICJ and ICC
- ICJ: the UN’s principal judicial organ; hears contentious cases between states and gives advisory opinions to authorised UN bodies.
- ICC: a permanent, treaty-based criminal court; investigates and tries individuals charged with genocide, crimes against humanity, war crimes or aggression.
- Location: both courts are based in The Hague, Netherlands.
- Core distinction: the ICJ considers state responsibility; the ICC considers individual criminal responsibility.
What do the ICJ and ICC do?
The ICJ applies international law to disputes submitted by states. Its work includes questions about treaties, borders, diplomatic relations and state obligations. The Court also issues advisory opinions when authorised United Nations organs or specialised agencies refer a legal question. The ICJ describes these two roles in its official mandate.
The United Nations Charter established the ICJ as the organisation’s principal judicial organ. The Court has 15 judges elected by the UN General Assembly and Security Council for nine-year terms. Its seat is at the Peace Palace in The Hague, and English and French are its official languages. Chapter XIV sets out its place in the UN system and the rules around compliance with judgments.
The ICC focuses on the conduct of people accused of the gravest crimes under international law. It can investigate and, where the evidence and legal requirements support a case, try individuals. The ICC’s mandate covers genocide, crimes against humanity, war crimes and the crime of aggression. Its founding treaty, the Rome Statute, also sets out the court’s jurisdiction, fair-trial protections and relationship with national courts.
The two institutions therefore answer different legal questions. An ICJ case asks what international law requires of a state in a dispute. An ICC case asks whether an accused person bears criminal responsibility for conduct within the Court’s jurisdiction.
ICJ vs ICC: how the courts compare
| Question | ICJ | ICC |
|---|---|---|
| Who appears before it? | States in contentious cases; authorised UN bodies and agencies may request advisory opinions. | Individuals accused of Rome Statute crimes. |
| What does it decide? | Legal disputes between states and advisory questions. | Individual criminal responsibility for four crimes listed in the Rome Statute. |
| What establishes its role? | UN Charter and Statute of the ICJ. | Rome Statute, adopted in 1998 and in force from 2002. |
| How can a matter begin? | A state files a contentious case under a recognised basis of jurisdiction; authorised UN bodies may request an advisory opinion. | A State Party referral, a Security Council referral or a prosecutor-initiated investigation under the Statute’s rules. |
| What can follow? | A judgment between the parties or an advisory opinion. | A trial, an acquittal or conviction, a sentence and, where appropriate, reparations. |
The table summarises the central difference; jurisdiction and procedure add important conditions. The ICJ’s jurisdiction rules explain how states give the Court authority to hear a contentious case. The ICC’s process guide describes the routes for investigations and cases.
How does jurisdiction differ?
For a contentious ICJ case, states must have accepted the Court’s jurisdiction through a relevant legal basis. That basis can arise through a special agreement for a particular dispute, a treaty clause or declarations accepting compulsory jurisdiction. The Court assesses jurisdiction at the start of a case, then determines whether the judges can hear it.
Advisory opinions follow another route. The UN General Assembly, Security Council and other authorised organs can ask the ICJ for advice on a legal question within their work. An advisory opinion gives the requesting body authoritative legal guidance, while a judgment binds the parties in the case before the ICJ. Courts, governments and international organisations may still use the reasoning to guide later decisions.
The ICC’s jurisdiction rests on the Rome Statute. A case can reach the Court when a crime took place on the territory of a State Party, when an accused person is a national of a State Party, when a state accepts the Court’s jurisdiction for a situation, or when the UN Security Council refers the situation. The Prosecutor can also seek authority to open an investigation on the Prosecutor’s own initiative under the Statute’s procedure.
These rules connect the ICC’s work with national courts. The Rome Statute gives domestic authorities the first opportunity to investigate and prosecute; the ICC acts as a court of last resort under the complementarity principle. The International Committee of the Red Cross’ Rome Statute guide summarises the treaty’s adoption on 17 July 1998 and entry into force on 1 July 2002.
How do cases begin and what outcomes can follow?
An ICJ contentious case begins with an application from one state against another. Written pleadings and public hearings allow the parties to present their legal arguments. The judges then issue a judgment that binds the parties in that case. Article 94 of the UN Charter describes members’ commitment to comply and gives the other party a route to the Security Council if a state fails to perform its obligations under a judgment.
The ICJ’s advisory work begins with a request from an authorised UN organ or agency. The Court receives written statements and may hold hearings before issuing its opinion. The result clarifies the legal question referred to the judges, while the requesting institution decides how to use that guidance in its own work.
At the ICC, the Prosecutor examines information and investigates situations within the Court’s jurisdiction. A case moves to trial when judges confirm the charges. The trial includes prosecution, defence and judicial review. Convictions can lead to imprisonment, fines, forfeiture and reparations for victims under the Rome Statute. The ICC relies on cooperation from states to carry out arrests and enforce sentences.
These enforcement arrangements reflect the courts’ different legal foundations. The ICJ works within the United Nations Charter system, while the ICC operates through a treaty joined by states. The ICC has its own judges, prosecutors and Registry; its relationship with the UN includes an agreement for cooperation.
Can one situation involve both courts?
Yes. A conflict or alleged international crime can create a dispute between states and raise questions about individual conduct. The two legal tracks remain separate: the ICJ considers the state-to-state claim under the law and jurisdiction relevant to that case; the ICC considers whether individuals face charges under the Rome Statute and whether the Court has jurisdiction.
For example, imagine one state alleges that another state breached a treaty, while investigators examine whether named officials or commanders committed Rome Statute crimes. The ICJ would assess the treaty dispute between the states if it had jurisdiction. The ICC would assess the individuals’ alleged conduct if the Statute’s jurisdiction conditions and evidential standards were met. Each court would apply its own process and issue its own decision.
This distinction helps readers interpret headlines about the same crisis appearing in court news from The Hague. A provisional-measures order, an advisory opinion, an arrest warrant and a final criminal judgment each carry a different legal meaning. The legal comparison by University of East Anglia scholars also explains how separate ICJ and ICC proceedings can relate to the same situation.
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ICJ and ICC: frequently asked questions
Are the ICJ and ICC the same court?
They are separate international courts with different statutes and legal roles. The ICJ hears state disputes and advisory questions, while the ICC tries individuals charged with crimes under the Rome Statute.
Who can bring a case to the ICJ?
States can bring contentious cases against other states when a recognised basis of jurisdiction applies. Authorised United Nations organs and specialised agencies can request an advisory opinion on a legal question.
Can the ICC prosecute a country?
The ICC tries individuals, including people who held public or military office. The ICJ handles legal disputes between states, including claims about a state’s treaty obligations.
Is the ICC part of the United Nations?
The ICC is an independent court created by the Rome Statute, a treaty. The ICJ is the principal judicial organ of the United Nations under the UN Charter.
Can both courts deal with the same conflict?
Yes. A state dispute can go to the ICJ when jurisdiction exists, while the ICC can examine individual conduct when its jurisdiction rules apply. Each court follows its own legal process and reaches its own decisions.
Last reviewed: 3 November 2026