Greater Somalia refers to those regions in the Horn of Africa in which Somalis live, as well as to the political vision of unifying these people under a unified Somali state . Greater Somalia thus encompasses Somalia/Somaliland, eastern Ethiopia, Djibouti and northeastern Kenya. The policy has led to conflict, with Somalia engaging in armed warfare twice with Ethiopia over the Ogaden region.

The first armed conflict began in 1963 in an ethnic Somali area, Elkere in Bale province. The revolt raged in Bale province for several years until a number of developments took the energy out of the militants, including the decision of Somali Prime Minister Mohammed Ibrahim Egal to focus his country's resources on economic development. Rebels began to surrender to the Ethiopians at the end of 1969; Waqo Gutu , who had been the foremost of the insurgents, was surrounded with his command of barely 200 men in Arana by the Ethiopian army in February 1970, and surrendered; pacification was complete by the next year.

From the late 1970s onwards, Mogadishu was forced to abandon the dream of recreating Greater Somalia. On 27 June 1977, Djibouti became a sovereign nation after 95% of its population voted against rejoining Somalia. Ethiopia scored a decisive victory in 1978 that ended the Ogaden War. In 1981, Siad Barre visited Nairobi, Kenya and stated that Somalia was relinquishing its claim on Kenyan territory. Improving relations with Kenya led to the signing of a pact in December 1984 ceasing all hostilities along the border. Following continued hostilites in Ogaden, Ethiopia and Somalia signed a peace treaty in 1988.

The vision of a Greater Somalia appears to have been abandoned as Somalia struggles to recover from decades of civil war.