The Soviet–Afghan War was a protracted armed conflict fought in the Soviet-controlled Democratic Republic of Afghanistan (DRA) from 1979 to 1989. The war was a major conflict of the Cold War as it saw extensive fighting between the DRA, the Soviet Union and allied paramilitary groups against the Afghan mujahideen and their allied foreign fighters. While the mujahideen were backed by various countries and organizations, the majority of their support came from Pakistan, the United States (as part of Operation Cyclone), the United Kingdom, China, Iran, and the Arab states of the Persian Gulf. The involvement of the foreign powers made the war a proxy war between the United States and the Soviet Union.[24] Combat took place throughout the 1980s, mostly in the Afghan countryside. The conflict led to the deaths of between 562,000 and 2,000,000 Afghans, while millions more fled from the country as refugees; most externally displaced Afghans sought refuge in Pakistan and in Iran. Approximately 6.5% to 11.5% of Afghanistan's erstwhile population of 13.5 million people (per the 1979 census) is estimated to have been killed over the course of the conflict. The Soviet–Afghan War caused grave destruction throughout Afghanistan and has also been cited by scholars as a significant factor that contributed to the dissolution of the Soviet Union, formally ending the Cold War.

The war began after the Soviets, under the command of Leonid Brezhnev, launched an invasion of Afghanistan to support the local pro-Soviet government that had been installed during Operation Storm-333. Numerous sanctions and embargoes were imposed on the Soviet Union by the international community in response. Soviet troops occupied Afghanistan's major cities and all main arteries of communication, whereas the mujahideen waged guerrilla warfare in small groups across the 80% of the country that was not subject to uncontested Soviet control—almost exclusively comprising the rugged, mountainous terrain of the countryside. In addition to laying millions of landmines across Afghanistan, the Soviets used their aerial power to deal harshly with both Afghan resistance and civilians, levelling villages to deny safe haven to the mujahideen, destroying vital irrigation ditches and other scorched-earth tactics.

The Soviet government had initially planned to swiftly secure Afghanistan's towns and road networks, stabilize the People's Democratic Party of Afghanistan (PDPA) government, and withdraw all of their military forces in a span of six months to one year. However, they were met with fierce resistance from Afghan guerrillas and experienced great operational difficulties on the rugged mountainous terrain. By the mid-1980s, the Soviet military presence in Afghanistan had increased to approximately 115,000 troops and fighting across the country intensified; the complication of the war effort gradually inflicted a high cost on the Soviet Union as military, economic, and political resources became increasingly exhausted. By mid-1987, reformist Soviet leader Mikhail Gorbachev announced that the Soviet military would begin a complete withdrawal from Afghanistan. The final wave of disengagement was initiated on 15 May 1988, and on 15 February 1989, the last Soviet military column occupying Afghanistan crossed into the Uzbek SSR. With continued external Soviet backing, the PDPA government pursued a solo war effort against the mujahideen, and the conflict evolved into the Afghan Civil War. However following the dissolution of the Soviet Union in December 1991, all support to the Republic was pulled, leading to the toppling of the Homeland Party's Isolated Republic at the hands of the mujahideen in 1992 and the start of another Afghan Civil War.