International Solidarity Day of Azerbaijanis (Azerbaijani: Dünya Azərbaycanlılarının Həmrəyliyi Günü) is an annual public holiday in Azerbaijan celebrating the worldwide solidarity and unity of Azerbaijanis.^[3] The day was inspired by the dismantling of border fences between Soviet Azerbaijan and Iran in December 1989 and the collapse of the Berlin Wall^[4] in the same year.

In 1989 the local residents took down the Soviet–Iranian border in then-Nakhichevan ASSR to reunite with Iranian Azerbaijanis.^[5] On the same day, the first World Congress of Azerbaijanis took place in Istanbul.

The day was first promoted on 16 December 1991 by then-Chairman of the Nakhchivan Autonomous Republic Supreme Assembly Heydar Aliyev. The various governments that have been in power since Azerbaijan's independence from the Soviet Union have all marked that day.^[6] Aliyev raised the issue before the Supreme Soviet of Azerbaijan SSR to declare that date a holiday at state level. The holiday eventually gained a state status in 1992, with Abulfaz Elchibey's presidential decree.

The day was entered into the Labor Code of Azerbaijan as a non-working day,^[7] coinciding with New Year's Eve, and is celebrated by Azerbaijani diaspora across the world.

• Congress of World Azerbaijanis