A peace treaty is a formal agreement between hostile parties, usually countries, that officially ends a state of war, distinguishing it from temporary ceasefires or armistices. Such treaties are crucial because the legal and political "state of war" does not automatically terminate when actual fighting stops, necessitating an agreement to address all transition issues like border designations, refugee status, and dispute resolution processes.

However, since 1950, the rate at which interstate wars conclude with a formal peace treaty has substantially declined. Under the United Nations system, military conflicts are increasingly referred to as 'international armed conflicts' instead of 'wars' to align with UN Charter Article 2, which restricts the use of military force. This shift often bypasses the conclusion of traditional peace treaties, as exemplified by the 2003 Iraq War, which was followed not by a treaty, but by UN Security Council Resolution 1483 to manage the post-war regime.