List of shortest-reigning monarchs

A monarch is the leader of a monarchy, a position usually intended to last for life or until abdication or deposition. The reigns of some monarchs have been notably short. Many of these monarchs acceded to the throne as a result of being first in an order of succession, while other monarchs claimed the throne as a result of conflict. The authenticity of some monarchs has been disputed, especially those who reigned during conflict. One factor in such debates is whether the monarch held the throne in a symbolic or nominal capacity.

Other monarchs who may have reigned for less than a year
The following monarchs may also have reigned for less than a year, but only an approximate length of reign is known.