The Azerbaijan Democratic Republic, also known as the Azerbaijan People's Republic, was the first secular democratic republic in the Turkic and Muslim worlds. The ADR was founded by the Azerbaijani National Council in Tiflis on 28 May 1918 after the collapse of the Transcaucasian Democratic Federative Republic, and ceased to exist on April 28, 1920. Its established borders were with Russia to the north, the Democratic Republic of Georgia to the north-west, the Republic of Armenia to the west, and Iran to the south. It had a population of around 3 million. Ganja was the temporary capital of the Republic as Baku was under Bolshevik control. The name of "Azerbaijan" which the leading Musavat party adopted, for political reasons, was, prior to the establishment of the Azerbaijan Democratic Republic in 1918, exclusively used to identify the adjacent region of contemporary northwestern Iran.

The Transcaucasian Democratic Federative Republic was a short-lived state in the Caucasus that included most of the territory of the present-day Armenia, Azerbaijan and Georgia, as well as parts of Russia and Turkey. The state lasted only for a month before Georgia declared independence, followed shortly after by Armenia and Azerbaijan.