The Armenian Genocide (Հայոց Ցեղասպանութիւն, Ermeni Soykırımı), also known as the Armenian Holocaust, the Armenian Massacres and, by Armenians, the Great Calamity (Մեծ Եղեռն) - refers to the deliberate and systematic destruction (genocide) of the Armenian population of the Ottoman Empire during and just after the First World War. It was characterised by the use of massacres, and the use of deportations involving forced marches under conditions designed to lead to the death of the deportees, with the total number of Armenian deaths generally held to have been between one and one-and-a-half million. Other ethnic groups were similarly attacked during this period, including Assyrians and Greeks and some scholars consider the events to be part of the same policy of extermination .

The date of the onset of the genocide is conventionally held to be April 24, 1915, the day that Ottoman authorities arrested some 250 Armenian intellectuals and community leaders in Istanbul. Thereafter, the Ottoman military uprooted Armenians from their homes and forced them to march for hundreds of miles, deprived of food and water, to the desert of what is now Syria. Massacres were indiscriminate of age or gender, and rape and other sexual abuse were commonplace. The Armenian Genocide is the second most-studied case of genocide. Rummel R. J. "The Holocaust in Comparative and Historical Perspective". The Journal of Social Issues. Volume 3, no.2. April 1, 1998. Retrieved April 30, 2007.

The Republic of Turkey, the successor state of the Ottoman Empire, does not accept the word genocide as an accurate description of the events. In recent years, it has faced repeated calls to accept the events as genocide. To date, twenty-two countries have officially recognized the events of the period as genocide, and most scholars and historians accept this view. The majority of Armenian diaspora communities were founded as a result of the Armenian genocide.