Galkayo (Somali: Gaalkacyo, Arabic: جالكعيو, Italian: Gallacaio also known as Rocca Littorio) is the third-largest city in Somalia and serves as the capital of the north-central Mudug region.

Geographically, Galkayo is divided into four main quarters: Garsoor, Horumar, Israac, and Wadajir. Galkayo is divided between the regional states of Puntland and Galmudug. It serves as the capital of the Galkayo District as well as the Mudug region, and it has grown considerably in recent times, becoming a commercial hub connecting southern Somalia with the northern parts of the country.

At its founding, the city was primarily inhabited by pastoralists, who sporadically fought in clan groups over resources like water and grazing land. In particular, the Darod, dominant in the north of the city, and the Hawiye, dominant in the south of the city, fought over the city due to their long-standing rivalry.

Galkayo was formally established in the late 19th century by Sultan Yusuf Ali Kenadid of the Hobyo Sultanate. Kenadid, as part of an ongoing power struggle with his rivals in the Majeerteen Sultanate, signed a treaty with the Kingdom of Italy to become a protectorate, thereby passing the city into nominal Italian control. Under Italian rule, the city's communities were split along the "Tomaselli Line" to prevent further conflict between the Darod and the Hawiye.

After World War II, Italian Somaliland became the Trust Territory of Somalia under the guidance of the United Nations. At this time, the city saw significant unity among rival groups due to growing Somali nationalism, spurred by the growing influence of the Somali Youth League, a Somali nationalist political party. Following the independence of Somalia in 1960, Galkayo was made the center of Galkayo District and the capital of Mudug region.

The city fell back into conflict during the rule of Siad Barre, who actively took advantage of class differences within the city to exercise his power. In particular, Barre, a member of a Darod subclan, backed the Darod people in their struggle over the city. On 12 November 1989, a group of Hawiye officers mutinied against Barre's regime for this clan favoritism. This mutiny was put down a day later by a militia led by Maslah Mohammed Barre, Siad Barre's son. Hawiye villages around Galkayo were punished in response to the mutiny by Barre's militia, furthering the divide between them and the Darod, and leading to a subsequent mutiny in Mogadishu on 5 December 1989.

During the Somali Civil War, the Hawiye rebel organization United Somali Congress attacked Darod elements in Galkayo, starting a major clan war surrounding the city and Mudug region as a whole. The fighting clans drew administrative borders through the city, splitting it between the Darod-controlled Puntland and the Hawiye-controlled Galmudug, strengthening the divide between them. As the fighting of the Somali Civil War became more violent, the United Nations intervened with United Nations Operation in Somalia II, and negotiated peace within the Mudug region and the withdrawal of militant fighters from Galkayo.

In June 1993, in order to end the fighting in Galkayo, it was decided to relocate the militias that were in conflict in the city to Wargalo, Buryaqab (Harfo) and Galdogob, which are 70 kilometers away.