The Nagorno-Karabakh Autonomous Oblast votes to secede from Azerbaijan and join Armenia, triggering the Nagorno-Karabakh War.

Nagorno-Karabakh war may refer to:

The Nagorno-Karabakh Autonomous Oblast (NKAO) was an autonomous oblast within the Azerbaijan Soviet Socialist Republic that was created on July 7, 1923. Its capital was the city of Stepanakert. The leader of the oblast was the First Secretary of the Nagorno-Karabakh Autonomous Oblast Committee of the Communist Party of Azerbaijan. The majority of the population were ethnic Armenians.