Armenian Genocide of 1915 was just the first one committed by Turkish Empire (Ottoman Empire) in 20th century, Turkish government repeatedly slaughtered their own citizens, who were not ethnic Turks.

- Greek Genocide that took place from 1914–1923 resulted in death of 700-900.000 people. (http://en.wikipedia.org/wiki/Greek_genocide)

- Assyrian genocide 1890s, 1914–1918, 1922–1925 resulted in death of 275-300.000 people. (http://en.wikipedia.org/wiki/Assyrian_genocide)

- Bulgarians were victims of brutalities as well. (http://en.wikipedia.org/wiki/Batak_massacre)

They were mostly Christian minorities.