The North Yemen Civil War begins when Abdullah al-Sallal dethrones the newly crowned Imam al-Badr and declares Yemen a republic under his presidency.

The North Yemen civil war, also known in Yemen as the 26 September Revolution, was a civil war fought in North Yemen from 1962 to 1970 between partisans of the Mutawakkilite Kingdom and supporters of the Yemen Arab Republic. The war began with a coup d'état carried out in 1962 by revolutionary republicans led by the army under the command of Abdullah al-Sallal. He dethroned the newly crowned King and Imam Muhammad al-Badr and declared Yemen a republic under his presidency. His government abolished slavery in Yemen. The Imam escaped to the Saudi Arabian border where he rallied popular support from northern Zaydi tribes to retake power, and the conflict rapidly escalated to a full-scale civil war.