Jurisdiction refers to the power of States to enforce their laws and authority (judicial and police actions) over persons and property.

The various bases of jurisdiction (eg territorial, passive personality, etc) are exercisable by States in accordance with their national laws, unless otherwise mandated by a treaty. In practice, this means that States are generally not obliged to exercise extraterritorial jurisdiction, this being exceptional and subject to sovereignty-based limitations.

Although a State may possess legitimate jurisdiction over a person or property, such jurisdiction may be suspended by the operation of a particular immunity. In this case, the jurisdiction is simply suspended, not extinguished. This means that when the immunity ceases to exist the court may validly assert jurisdiction once again.

Jurisdiction may be civil or criminal in nature. In the latter case, it refers only to powers over persons. International law textbooks and university courses do not as a general rule deal with civil jurisdiction, save for legal actions brought against State entities and international organizations on commercial grounds (eg debts incurred by embassies or public corporations). Other law suits concerning private transnational disputes, for example family, property, or tort, are resolved by reference to the jurisdictional rules of the forum country (ie the country where the suit is lodged) as well as by specific international treaties that resolve jurisdictional conflicts in these fields. This area of law is known as private international law or otherwise as conflict of laws.

The jurisdiction exercised by a domestic court may be in conflict with the jurisdiction available to the courts of several other countries, especially where all of these possess a link with the crime, the offender, or the victims. Jurisdictional conflicts of this nature are best dealt with through inter-State cooperation, as is the case with extradition, through existing treaties, or by ad hoc agreements. The jurisdiction of national courts may moreover be complementary (ie parallel) with that of international courts or tribunals. The statutes of the respective tribunals will determine which of the two has primary jurisdiction. There is nothing awkward about more than one State having legitimate claims of jurisdiction over a case. In fact, sometimes international law aims to give jurisdiction to as many States as possible (eg in respect of transnational crimes) as a means of ensuring the administration of justice.