List of longest-reigning monarchs

This is a list of the longest-reigning monarchs in history, detailing the monarchs and lifelong leaders who have reigned the longest, ranked by length of reign.

Monarchs of sovereign states with verifiable reigns by exact date

The following are the 25 longest-reigning monarchs of states who were internationally recognised as sovereign for most or all of their reign. Roman emperors Constantine VIII and Basil II, reigning for 66 years in total (962–1028) and for 65 years in total (960–1025) respectively, are not included, because for part of those periods they reigned only nominally as junior co-emperors alongside senior emperors.

Regencies (and coregencies as a "senior" monarch) are not counted against monarchs, hence Louis XIV is listed first among the monarchs of sovereign states despite his mother Anne of Austria being his regent for eight years. A distinction is not made between absolute and constitutional monarchs, hence Elizabeth II is listed second despite being a figurehead her entire reign.

The currently living longest-reigning monarch, Hassanal Bolkiah of Brunei, is not included on the list because Brunei was not a sovereign state until 1 January 1984.

Monarchs of dependent or constituent states with verifiable reigns by exact date

The table below contains 100 monarchs of states that were not independent sovereigns for at least a portion of their reigns.