Jurisdiction describes the underlying authority for a court or other tribunal to hear and decide a matter before it. A court may not make a judgment or require parties to appear before it unless it has jurisdiction over the dispute. Jurisdiction may be exercised or declined on a number of grounds. Moreover, just because one court or tribunal has jurisdiction over a dispute does not preclude the possibility that another court or tribunal may also have jurisdiction (see Conflict of laws).

Jurisdiction may be asserted on a number of grounds:

Subject matter jurisdiction - A court may have jurisdiction if the dispute is above or below a certain monetary limit. It may also have jurisdiction over the relief being sought by the complainant, such as whether they are seeking monetary damages or a restraining order. Lastly some systems use specialized tribunals for the settlement of certain types of dispute, such as landlord and tenant matters.

Territorial jurisdiction - Courts may generally only assert jurisdiction over disputes which have a real and substantial connection to territory where the court is located. For a crime, this is often where the crime took place, but may also be the country where the alleged perpetrator is a citizen.

In personam jurisdiction - Courts may assert jurisdiction over persons that fall within the operation of their law. For example, a lawyer discipline tribunal in New York State has jurisdicition to hold disciplinary hearings on all lawyers licensed to practice in that state no matter where they are physically located or where alleged misconduct is thought to have taken place.

In rem jurisdiction - Courts generally have jurisdiction over real property in the territory, as well as any personal property that is temporarily present within that territory. For example, a court in New Orleans may have jurisdiction over the disposition of a ship registered in England if the ship is in port.

Universal jurisdiction - For some crimes, such as piracy, war crimes, torture or genocide, it is accepted that any court may exercise jurisdiction over an individual even if jurisdiction cannot be justfied on any of the bases above. For example, many crimes related to the Holocaust were tried in Israel.