List of military disasters

In this list a military disaster is the unexpected and sound defeat of one side in a battle or war, sometimes changing the course of history.

Military disasters in this list can range from a strong army losing a major battle against a clearly inferior force, to an army being surprised and defeated by a clearly superior force, to a seemingly evenly matched conflict with an extremely one sided result. A military disaster could be due to bad planning, bad execution, bad weather, general lack of skill or ability, the failure of a new piece of military technology, a major blunder, a brilliant move on the part of the enemy, or simply the unexpected presence of an overwhelming enemy force.

One definition of military disaster describes the presence of two or three factors:

According to this definition, two particular characteristics are not necessary for an event to be classified as a military disaster:

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