Libya's relations with Sudan, like relations with virtually all other Arab and African countries, fluctuated. Initially, Libya supported Sudanese President Jaafar an Numayri against an unsuccessful leftist coup attempt in 1971. Libya turned over two of the top communist plotters to the Sudanese authorities, who executed them shortly afterward. However, a year later Sudan accused Libya of involvement in three successive coup attempts and severed diplomatic relations. Relations began improving by the fall of 1977, as Numayri and Sudanese opposition leaders began a reconciliation. In February 1978, Libya and Sudan agreed to resume relations but relations soon became strained after Qadhafi condemned Sudanese support for President Anwar al Sadat of Egypt and for the Camp David accords of September 1978.

Libya was particularly annoyed by the steadily improving relations between Sudan and Egypt during the closing years of the Numayri regime, which culminated eventually in an Egyptian-Sudanese integration charter that provided Egypt with an air base in Sudan that could serve as a counterweight to Libyan regional power. Feeling threatened by the Cairo-Khartoum alliance and its alignment with the West, in August 1981 Qadhafi formed the Tripartite Alliance with Ethiopia and South Yemen PDRY, each of which was aligned closely with the Soviet Union.

After Numayri's fall from power in April 1985, Sudanese-Libyan relations improved. Qadhafi ended his aid to the Christian and animist, southern-based, Sudanese People's Liberation Army (SPLA) led by Garang and welcomed the incoming government of General Sawar Dhahab. In July 1985, a military protocol was signed between the two countries, and Qadhafi was the first head of state to visit the new Khartoum government. Qadhafi then strongly supported Sudanese opposition leader Sadiq al Mahdi, who became prime minister on May 6, 1986. Nonetheless, the initial euphoria was subsequently replaced by Sudan's search for a truly neutral regional and global stance. With regard to the Chadian conflict, for instance, Mahdi's government declared its neutrality and asked that Libyan forces be withdrawn from Sudanese territory. Prime Minister Mahdi's attempts to mediate the Libyan-Chadian conflict have so far proved unsuccessful, although delegations from the warring factions have met several times during 1986 and 1987, under Sudanese aegis.

Data as of 1987