Mass suicide occurs when a number of people kill themselves together.
Mass suicide sometimes occurs in religious or cultic settings. Defeated groups may resort to mass suicide rather than being captured. Suicide pacts are a form of mass suicide unconnected to cults or war that are sometimes planned or carried out by small groups of frustrated people. Mass suicides have been used as a form of political protest.
Notable mass suicides 
- During the late 2nd century BC, the Teutons are recorded as marching south through Gaul along with their neighbors, the Cimbri, and attacking Roman Italy. After several victories for the invading armies, the Cimbri and Teutones were then defeated by Gaius Marius in 102 BC at the Battle of Aquae Sextiae (near present-day Aix-en-Provence). Their King, Teutobod, was taken in irons. The captured women committed mass suicide, which passed into Roman legends of Germanic heroism: by the conditions of the surrender three hundred of their married women were to be handed over to the Romans. When the Teuton matrons heard of this stipulation, they first begged the consul that they might be set apart to minister in the temples of Ceres and Venus; then, when they failed to obtain their request and were removed by the lictors, they slew their children and next morning were all found dead in each other's arms having strangled themselves in the night.
- At the end of the fifteen months of the siege of Numantia in summer 133 BC most of the defeated Numantines, instead of surrendering, preferred to commit suicide and set fire to the city.
- The 960 members of the Sicarii Jewish community at Masada collectively committed suicide in AD 73 rather than be conquered and enslaved by the Romans. Each man killed his wife and children, then the men drew lots and killed each other until the last man killed himself.
- The occasional practice of mass suicide known as Jauhar was carried out in medieval times by Rajput communities in India, when the fall of a city besieged by Muslim invaders was certain, in order to avoid capture and dishonour. The best known cases of Jauhar are the three occurrences at the fort of Chittaur in Rajasthan, in 1303, in 1535, and 1568.
- In 1336, when the castle of Pilėnai (in Lithuania) was besieged by the army of the Teutonic Knights, the defenders, led by the Duke Margiris, realized that it was impossible to defend themselves any longer and made the decision to commit mass suicide, as well as to set the castle on fire in order to destroy all of their possessions, and anything of value to the enemy.
- During the Turkish rule of Greece and shortly before the Greek War of Independence, women from Souli, pursued by the Ottomans, ascended the mount Zalongo, threw their children over the precipice and then jumped themselves, to avoid capture - an event known as the Dance of Zalongo.
- On 1 May 1945, about 1,000 residents of Demmin, Germany, committed mass suicide after the Red Army had sacked the town.
- A Balinese mass ritual suicide is called a puputan. Major puputan occurred in 1906-1908 when Balinese kingdoms faced overwhelming Dutch colonial forces. The root of the Balinese term puputan is puput, meaning 'finishing' or 'ending'. It is an act that is more symbolic than strategic; the Balinese are "a people whose genius for theatre is unsurpassed" and a puputan is viewed as "the last act of a tragic dance-drama".
- Japan is known for its centuries of suicide tradition, from seppuku ceremonial self-disemboweling to kamikaze warriors flying their aircraft into Allied warships during World War II. During this same war, the Japanese stated to the people of Saipan that the invading American troops were going to torture and murder anyone on the island. In a desperate effort to avoid this, the people of Saipan committed suicide, mainly by jumping off the nearby cliffsides.
- The Jonestown suicides in Guyana, where 914 members of the Peoples Temple, led by Jim Jones, died in 1978. Of the 918 dead (including four in Georgetown and five non-members at an airstrip), 276 were children. On a tape of their final meeting, Jones tells Temple members that the Soviet Union, with whom the Temple had been negotiating a potential exodus for months, would not take them after the Temple had murdered Congressman Leo Ryan, NBC reporter Don Harris and three others at a nearby airstrip. When members apparently cried during what the Temple called "revolutionary suicide," Jones counseled "Stop this hysterics. This is not the way for people who are Socialists or Communists to die. No way for us to die. We must die with some dignity."
- The Order of the Solar Temple mass suicide killed 74 people in two towns in Switzerland and one in Canada in October 1994. About two thirds of the deaths were murders, including the ritual murder of a newborn child.
- The Heaven's Gate mass suicide occurred in a hilltop mansion near San Diego, California, in 1997. They believed an alien spaceship was following in the tail of the Comet Hale-Bopp and that killing themselves was necessary to reach it. They were cited on their website as wishing to reach the next plane of existence. The victims were self-drugged and then suffocated by other members in a series of suicides over a period of three days. Thirty-nine people died.
- The 778 deaths of members of the Ugandan group Movement for the Restoration of the Ten Commandments of God, on 17 March 2000, is considered to be a mass murder and suicide orchestrated by leaders of the group.
See also 
- Holology: Mass Suicide
- Lucius Annaeus Florus, Epitome 1.38.16-17 and Valerius Maximus, Factorum et Dictorum Memorabilium 6.1.ext.3
- Masada and the first Jewish revolt against Rome: Near East Tourist Industry, Steven Langfur 2003
- Rajasthan: Monique Choy, Sarina Singh p.231 ISBN 1-74059-363-4, Lonely Planet Publications, Oct 2002 
- GEDIMINO LAIŠKAI: The Letters of Gediminas, the Great Duke of Lithuania (appr. 1275 - 1341)
- Memorials and Other Papers:Thomas de Quincey, ISBN 0-14-043015-6
- Lakotta, Beate (2005-03-05). "Tief vergraben, nicht dran rühren" (in German). SPON. Retrieved 2010-08-16.
- Pringle, p 106
- 1978: Mass suicide leaves 900 dead BBC News, "On this day", 18 November 1978
- "Jonestown Audiotape Primary Project." Alternative Considerations of Jonestown and Peoples Temple. San Diego State University.
- How the Millennium Comes Violently: From Jonestown to Heaven's Gate: Catherine Wessinger, ISBN 1-889119-24-5 p218
- Solar Temple: A cult gone wrong CBC Archives
- Mass graves found in sect house Anna Borzello The Guardian 25 March 2000
- Cult in Uganda Poisoned Many, Police Say New York Times 28 July 2000
- Pringle, Robert (2004). Bali: Indonesia's Hindu Realm; A short history of. Short History of Asia Series. Allen & Unwin. ISBN 1-86508-863-3.