A military disaster is the defeat of one side in a battle or war which results in the complete failure of the losing side to achieve their objectives. It often, but not always, involves a high and disproportionate loss of life. The causes are varied and include human error, inferior technology, logistical problems, underestimating the enemy, being outnumbered, and bad luck.[1][2][3][4]
Entries on this list are those where multiple sources dealing with the subject of military disasters have deemed the event in question to be a military disaster (or an equivalent term).
Syracuse Expedition (415–413 BC).[9][10] A large force from Athens failed to conquer the city of Syracuse, weakening the Athenian military position and depriving the city of much-needed manpower.
Battle of Carrhae (53 BC).[17][18]Crassus with 40,000 soldiers marched into Parthia, expecting to be victorious, chose to march a direct route through the desert instead of the mountains of the north. He and his army were entirely annihilated by 9,000 Parthian soldiers.
Battle of Tours (732).[23][24] The Muslim Moors marched into southern France meeting no foes, until encountering the Christian Frankish forces led by Charles Martel at Tours. Despite the Moorish advantage over the Franks militarily, they were defeated decisively by the Franks.
Spanish Armada (1588).[30][28][pageneeded] An English fleet sent fire ships into the Spanish invasion fleet destroying some and scattering the rest effectively ending the invasion threat. The Armada would later run into storms and almost half the ships never returned to Spain, as well as more than half of the troops.
Charge of the Light Brigade (1854).[32][28][pageneeded] A British cavalry unit charged an active enemy artillery position due to miscommunication and suffered heavy casualties for no real advantage.
Battle of Isandlwana[35][10] (January 22, 1879). In the first major battle of the Anglo-Zulu War, a Zuluimpi overwhelmed and defeated two battalions armed with modern rifles and artillery. The battle was a major victory for the Zulus during the opening stages of the war.
Withington, John (2016-09-23). "Introduction". Britain's 20 Worst Military Disasters: From the Roman Conquest to the Fall of Singapore. History Press. ISBN978-0-7509-8127-9.
Chrystal, Paul (2015-11-30). "The First Century: the Social War, Spartacus, Mithridates, Crassus, the Parthians, and the Gauls". Roman Military Disasters: Dark Days & Lost Legions. Pen and Sword. ISBN978-1-4738-7395-7. Carrhae was the worst Roman disaster, and Rome's darkest day, since the catastrophic Battle of Cannae in 216 BC some 163 years earlier.
Withington, John (2016-09-23). "Gallipoli, 1915". Britain's 20 Worst Military Disasters: From the Roman Conquest to the Fall of Singapore. History Press. ISBN978-0-7509-8127-9.
Willmott, H. P. (1983). The Barrier and the Javelin: Japanese and Allied Strategies, February to June 1942. United States Naval Institute Press. pp.396, 518. ISBN978-1-59114-949-1.
McNab, Chris (2005). The World's Worst Military Disasters: Chronicling the Greatest Battlefield Catastrophes of All Time. Rochester: Grange Books. ISBN978-1-84013-808-5.
Military Intelligence Blunders and Cover-Ups, by Colonel Hughes-Wilson John (ISBN978-0-7867-1373-8)