The Saur Revolution or Sowr Revolution, also known as the April Revolution or the April Coup, was staged on 27–28 April 1978 by the People's Democratic Party of Afghanistan (PDPA) and overthrew Afghan president Mohammed Daoud Khan, who had himself taken power in the 1973 Afghan coup d'état and established an autocratic one-party system in the country. Daoud and most of his family were executed at the Arg in the capital city of Kabul by Khalqi military officers, after which his supporters were also purged and killed. The successful PDPA uprising resulted in the creation of a socialist Afghan government that was closely aligned with the Soviet Union, with Nur Muhammad Taraki serving as the PDPA's General Secretary of the Revolutionary Council. Saur or Sowr is the Dari-language name for the second month of the Solar Hijri calendar, during which the events took place.

The Democratic Republic of Afghanistan (DRA), renamed the Republic of Afghanistan in 1987, was the Afghan state during the one-party rule of the People's Democratic Party of Afghanistan (PDPA) from 1978 to 1992. It relied heavily on assistance from the Soviet Union for most of its existence, especially during the Soviet–Afghan War.