The Green March was a strategic mass demonstration in November 1975, coordinated by the Moroccan government, to force Spain to hand over the disputed, autonomous semi-metropolitan Spanish Province of Sahara to Morocco.

Morocco, to the north of the Spanish Sahara, had long claimed that the territory was historically an integral part of Morocco. Mauritania to the south argued similarly that the territory was in fact Mauritanian. Since 1973, a Sahrawi guerrilla war led by the Polisario Front had challenged Spanish control, and in October 1975 Spain had quietly begun negotiations for a handover of power with leaders of the rebel movement, both in El Aaiún, and with foreign minister Pedro Cortina y Mauri meeting El Ouali in Algiers.

Morocco intended to vindicate its claims by demanding a verdict from the International Court of Justice (ICJ), which was issued on Oct. 16, 1975. The ICJ stated that there were historical legal ties of allegiance between "some, but only some" Sahrawi tribes and the Sultan of Morocco, as well as ties including some rights relating to the land between Mauritania and other Sahrawi tribes. [1] However, the ICJ stated also that there were no ties of territorial sovereignty between the territory and Morocco, or Mauritania, at the time of Spanish colonization; and that these contacts were not extensive enough to support either country's demand for annexation of the Spanish Sahara. Instead, the court argued, the indigenous population (the Sahrawis) were the owners of the land, and thus possessed the right of self-determination. This meant that regardless of which political solution was found to the question of sovereignty (integration with Spain, Morocco, Mauritania, partition, or independence), it had to be explicitly approved by the people of the territory. Complicating matters, a UN visiting mission had concluded on October 15, the day before the ICJ verdict was released, that Sahrawi support for independence was "overwhelming".