An interior ministry (sometimes ministry of home affairs) is a government ministry typically responsible for policing, national security, and immigration matters. The ministry is often headed by a minister of the interior. In some countries, matters relating to the maintenance of law and order and the administration of justice are the responsibility of a separate justice ministry.
In countries with a federal constitution, an interior minister will often be found at both the federal and state levels. Similarly, autonomous entities and dependent territories may also have interior ministers.