The Cuban intervention in Angola (codenamed Operation Carlota) began on 5 November 1975, when Cuba sent combat troops in support of the communist-aligned People's Movement for the Liberation of Angola (MPLA) against the pro-western coalition of the National Union for the Total Independence of Angola (UNITA), and the National Liberation Front of Angola (FNLA). The intervention came after the outbreak of the Angolan Civil War, which occurred after the former Portuguese colony was granted independence after the Angolan War of Independence. The previously unimportant civil war quickly developed into a major proxy war between the Eastern Bloc (led by the Soviet Union) and the Western Bloc (led by the United States). Apartheid South Africa and the United States backed UNITA and the FNLA, while communist nations backed the MPLA.George, p. 1Smith, pp. 66, 71–72

Around 4,000 Cuban troops fought to push back a three-pronged advance by the SADF, UNITA, FNLA, and Zairean troops. 18,000 Cuban troops then proved instrumental in defeating FNLA forces in the north and UNITA in the south. The Cuban army helped assist the MPLA in repressing separatists from the Front for the Liberation of the Enclave of Cabinda (FLEC). By 1976, the Cuban military presence in Angola had grown to nearly 36,000 troops. By effectively driving out the internationally isolated South African forces, Cuba was able to secure control over all the provincial capitals in Angola. Following the withdrawal of Zaire and South Africa, Cuban forces remained in Angola to support the MPLA government against UNITA in the continuing civil war. South Africa spent the following decade launching bombing and strafing raids from its bases in South West Africa into southern Angola, while UNITA engaged in ambushes, hit-and-run attacks, and harassment of Cuban units.

In 1988, Cuban troops, now amounting to around 55,000 troops, intervened to avert a military disaster in a Soviet-led People's Armed Forces of Liberation of Angola (FAPLA) offensive against UNITA, which was still supported by South Africa, leading to the Battle of Cuito Cuanavale and the opening of a second front. This turn of events was considered to have been the major impetus to the success of the ongoing peace talks leading to the 1988 New York Accords, the agreement by which Cuban and South African forces withdrew from Angola while South West Africa gained its independence from South Africa.George, p. 3Film Une Odyssée Africaine (France, 2006, 59 min) directed by: Jihan El TahriGleijesesCuito Cuanavale – "Afrikas Stalingrad", Ein Sieg über Pretorias Apartheid" in: Neues Deutschland, 19/20 April. 2008Campbell, Horace: The Military Defeat of the South Africans in Angola in: Monthly Review, April 1989 Cuban military engagement in Angola ended in 1991, while the Angolan Civil War continued until 2002. Between 1975 and 1991, Cuban casualties in Angola totaled approximately 10,000 dead, wounded, or missing. Between 1975 and 1989, during the Cuban intervention, more than 500,000 Angolans were killed (either in combat or indirectly through bombing, landmines, and starvation), at least another 500,000 were injured or crippled, and over $30 billion in damage was inflicted on Angola.George, p. 281

Background Failure of the Alvor Agreement and Civil War

The Carnation Revolution began in Portugal on 25 April 1974. The revolution took the world by surprise and caught the independence movements in Portugal's last African colonies unprepared.George, pp. 50–52 As a result of negotiations between Portugal and the Liberation Front of Mozambique, Mozambique was granted independence on 25 June 1974, but Angolan control remained disputed between the three rival independence movements: MPLA, FNLA, and UNITA in Angola-proper and the Front for the Liberation of the Enclave of Cabinda (FLEC) in Cabinda.

Until independence, the movements' priority lay in fighting the colonial power and they initially had no clear alliances. With the disappearance of Portugal as their common foe, ethnic and ideological rivalries were prioritized. Fighting between the three already broke out in November 1974, starting in Luanda and quickly spreading across all of Angola. The new leftist Portuguese government showed little interest in interfering but often favored the MPLA. The country soon fell apart into different spheres of influence, the FNLA taking hold of northern Angola and UNITA in the central south. The MPLA mostly held the coastline, the far southeast, and, in November 1974 gained control of Cabinda.George, p. 55 The disunity of the three main movements postponed the handing over of power. The Alvor Agreement, which the three and Portugal signed on 15 January, proved not to be a solid foundation for the procedure. The transitional government that the agreement provided for was equally composed of the three main independence movements and Portugal. It was sworn in on 31 January 1975; Independence Day was set for 11 November 1975, the same day as the ceasefire.Smith, p. 66 FLEC was not part of the deal because it fought for the independence of Cabinda, which the Portuguese had administratively joined as an exclave to Angola.

Fighting in Luanda (referred to as the "Second War of Liberation" by the MPLA) resumed hardly a day after the transitional government took office,George, p. 59 when Agostinho Neto took advantage of the ceasefire to launch a purge of his rival Daniel Chipenda's supporters within the MPLA. The Chipenda faction was largely annihilated, leaving the FLNA as the only remaining obstacle to MPLA control of the city. Chipenda and 2,000 of his surviving troops defected to FLNA around February, which further heightened tensions. FNLA troops, flown in from Zaire, had been taking positions in Luanda since October 1974. The MPLA followed later in smaller numbers.Gleijeses, p. 250 To that point, the MPLA and UNITA "had given every sign of intending to honour the Alvor agreement".Smith, p. 68 However, fighting broke out in Luanda between the FNLA and the MPLA. The FNLA was backed by Mobutu, the U.S., and China. By March, the FNLA from northern Angola was driving on Luanda joined by units of the Zairian army which the U.S. had encouraged Mobutu to provide.Norton, W.: In Search of Enemies: A CIA Story, New York, 1978, quoted in: Smith, p. 67

On 28 April 1975, the FNLA unleashed a second wave of attacks, and in early May, 200 Zairian troops crossed into northern Angola in its support.Wright, George in: The Destruction of a Nation: United States' Policy toward Angola since 1945, Pluto Press, London, Chicago, 1997, , p. 60George, p. 63 Neto requested the Soviets increase its military aid to the MPLA. During March 1975, Soviet pilots flew thirty planeloads of weapons into Brazzaville, where they were then transported to Luanda. The Soviet Union airlifted thirty million dollars' worth of weaponry to the MPLA in three months, while Cuba deployed a contingent of 230 military advisers and technicians to the MPLA, with the first advisers arriving in May.

The fighting intensified with street clashes in April and May, and UNITA became involved after over two hundred of its members were massacred by an MPLA contingent in June 1975. The initially weaker MPLA retreated south, but with supplies finally arriving from the Soviet Union then succeeded in driving the FNLA out of Luanda by 9 July 1975, and UNITA voluntarily withdrew to its stronghold in the south. The FNLA took up positions east of Quifangondo at the eastern outskirts of the capital, from where it kept up its pressure and eliminated all remaining MPLA presence in the northern provinces of Uíge and Zaire.

By August, the MPLA had control of 11 of the 15 provincial capitals, including Cabinda and Luanda.Smith, pp. 68, 70 The fight had spread throughout the whole country. The independence movements attempted to seize key strategic points, most importantly the capital on the independence day.

Foreign involvement Starting in the early 1960s, the three major independence movements received support from a wide range of countries, sometimes even from the same ones. By the time of independence, FNLA and UNITA had received aid from the United States, Zaire, South Africa, and China.

As long as Portugal was present in Angola, the movements had to have their headquarters in independent neighbouring countries, making Congo-Léopoldville (Democratic Republic of the Congo, formerly Belgian), for both MPLA and FNLA a logical choice. After its expulsion from Kinshasa in November 1963, the MPLA moved across the Congo River to formerly French Congo-Brazzaville in the Republic of the Congo where it was invited by its new leftist government.George, p. 10 The FNLA stayed in Congo-Léopoldville to which it remained closely tied and from where it received the bulk of its support. FNLA leader Holden Roberto was linked to Mobutu by marriage and obligated to him for many past favours. Over the years, the FNLA had become little more than an extension of Mobutu's own armed forces. Much of Zaire's support came indirectly from the U.S., which Zaire's leader Mobutu had close ties with. Zaire was the first country to send troops to Angola in March 1975 and to engage in fighting against the MPLA by the summer of that year.IPRI—Instituto Português de Relações Internacionais : The United States and the Portuguese Decolonization (1974-1976) Kenneth Maxwell, Council on Foreign Relations. Paper presented at the International Conference "Portugal, Europe and the United States", Lisbon, October 2003

In the summer of 1974, China was first to act after the Portuguese Revolution and posted 200 military instructors to Zaire where they trained FNLA troops and supplied military assistance. Chinese involvement was a measure against Soviet influence rather than that from western countries. On 27 October 1975, they were also the first to withdraw their military instructors. UNITA, which split away from FNLA in 1965/66 was initially Maoist and received some support from China. China had been training Mobutu's elite division, the Kamanyola, also trained the FNLA but withdrew their support for Zaire and the FNLA by the end of December 1975.Klinghoffer, A. J. in: The Angolan War: A Study in Soviet Policy in the Third World, Boulder, 1980 In 1975 China were also the first to pull out of the area after the Portuguese Revolution. When their support ceased FNLA and UNITA became firmly established in the western camp.

The United States had a history of supporting the Salazar regime in Portugal. They allowed NATO equipment to be used in Angola during the Independence War.George, p. 14 U.S. support for the FNLA was taken up by the Kennedy administration in 1960. Holden Roberto had been on the Central Intelligence Agency's or CIA's payroll since 1963.Smith, p. 70 On 7 July 1974, the CIA started funding the FNLA on a small scale.George, p. 54 On 22 January 1975, one week after the Alvor Accords were signed and just before the provisional government of Angola was to take office, the U.S. National Security Council's "40 Committee", which oversaw clandestine CIA operations, authorized US$300,000 in covert aid to the FNLA.