The 1982 Lebanon War - Operation Peace of the Galilee - Mivtsa Shlom HaGalil or Mivtsa Sheleg‎), and later colloquially also known in Israel as the First Lebanon War, began June 6, 1982, when the Israel Defense Forces invaded southern Lebanon. The Government of Israel ordered the invasion as a response to the assassination attempt against Israel's ambassador to the United Kingdom, Shlomo Argov by the Abu Nidal Organization. See also Operation Litani.

After attacking PLO, Syrian and Muslim Lebanese forces, Israel occupied southern Lebanon. Surrounded in West Beirut and subject to heavy bombardment, the PLO and the Syrian forces negotiated passage from Lebanon with the aid of international peacekeepers.

After the 1948 Arab-Israeli conflict, Lebanon became home to more than 110,000 Palestinian refugees from their homes in present day Israel. In 1970 and again in 1971, the PLO was engaged in the attempted overthrow of the Jordanian monarchy,^[7] which routed a large number of Palestinian fighters and refugees into Lebanon. By 1975, they numbered more than 300,000, creating an informal state-within-a-state in South Lebanon. The PLO became a powerful force and played an important role in the Lebanese Civil War. Continual violence occurred between Israel and the PLO from 1968, peaking in Operation Litani.