The Ugandan Bush War, also known as the Luwero War, the Ugandan Civil War or the Resistance War, was a civil war fought in Uganda by the official Ugandan government and its armed wing, the Uganda National Liberation Army (UNLA), against a number of rebel groups, most importantly the National Resistance Army (NRA), from 1980 to 1986.

The unpopular President Milton Obote was overthrown in a coup d'tat in 1971 by General Idi Amin, who established a military dictatorship. Amin was overthrown in 1979 following the Uganda-Tanzania War, but his loyalists started the Bush War by launching an insurgency in the West Nile region in 1980. Subsequent elections saw Obote return to power in a UNLA-ruled government. Several opposition groups claimed the elections were rigged, and united as the NRA under the leadership of Yoweri Museveni to start an armed uprising against Obote's government on 6 February 1981. Obote was overthrown and replaced as president by his general Tito Okello in 1985 during the closing months of the conflict. Okello formed a coalition government consisting of his followers and several armed opposition groups, which agreed to a peace deal. In contrast, the NRA refused to compromise with the government, and conquered much of western and southern Uganda in a number of offensives from August to December 1985.

The NRA captured Kampala, Uganda's capital, in January 1986. It subsequently established a new government with Museveni as president, while the UNLA fully disintegrated in March 1986. Obote and Okello went into exile. Despite the nominal end of the civil war, numerous anti-NRA rebel factions and militias remained active, and would continue to fight Museveni's government in the next decades.

The National Resistance Army (NRA), the military wing of the National Resistance Movement (NRM), was a rebel army that waged a guerrilla war, commonly referred to as the Ugandan Bush War or Luwero War, against the government of Milton Obote, and later that of Tito Okello.

NRA was supported by Muammar Gaddafi.NRA was formed in 1981 when Yoweri Museveni's Popular Resistance Army (PRA) merged with ex-president Yusuf Lule's group, the Uganda Freedom Fighters (UFF). Museveni, then leader of the Uganda Patriotic Movement party, alleged electoral fraud and declared an armed rebellion, following the victory of Uganda Peoples Congress in the bitterly disputed 1980 general election.Museveni, who had guerrilla war experience with the Mozambican Liberation Front (FRELIMO) in Mozambique, and his own Front for National Salvation (FRONASA) formed in Tanzania to fight Idi Amin, led the NRA to victory against Ugandan government troops (UNLA) in 1986. By the time that the victorious NRA entered Kampala in 1986, about a quarter of its 16,000 combatants were Banyarwanda, while Fred Rwigema was its deputy commander. The NRA then became the national army.

Shortly afterwards the UNLA carried out a number of attacks against civilians in the north of Uganda. The attacks largely targeted the Acholi people and were in part seen as a form of revenge for Operation Bonanza, the scorched-earth operation there that had been ordered by Milton Obote during his presidency.From 1986 to 1990, the Museveni regime tried to end various insurgencies and to establish control over the army. Despite repeated government claims that the NRA had defeated the UNLA and other rebel groups, insurgent activity continued, especially in the northern, eastern, and western regions. In April 1988, 3,000 former Uganda People's Army (UPA) fighters and members of several other small rebel groups accepted a government amnesty by surrendering and declaring their support for Museveni's regime. In June 1988, the president concluded a peace agreement with Uganda People's Democratic Army (UPDA) commander Lieutenant Colonel John Angelo Okello. Although the NRA subsequently integrated many UPA and UPDA personnel into its ranks, thousands of others rejected the peace accord and continued to fight against the NRA.

After the 1995 Ugandan constitution was enacted, the NRA was renamed the Uganda People's Defence Force.