Historians date the start of Operation Litani to 14 March (de Clerck and Malsagne, Traboulsi, Quéméner; de Clerck's chronology gives 15 March) and its end to 21 March. Up to 25,000 Israeli soldiers and 120 tanks took part (de Clerck and Malsagne). Estimates of the dead range from about 300 Palestinian fighters (de Clerck and Malsagne) to about 2,000 people, mostly civilians (Fisk; de Clerck and Malsagne; Picard). Estimates of the displaced range from 150,000 (Hanf's refugee table) and more than 200,000 (de Clerck and Malsagne, Picard) to 285,000 (Lebanese government figure cited by Fisk). On 15 March Israeli aircraft bombed the Palestinian camps of Beirut, Tyre and Damour.

Resolution 425 was adopted with Resolution 426, which set up the force; the USSR abstained (de Clerck and Malsagne). UNIFIL later numbered about 6,000 soldiers, with France providing the largest first contingent (1,290 men).

Fisk dates the arrival in Tyre of UNIFIL's first unit, Colonel Jean Germain Salvan's French paratroopers, to 23 March. That morning, at the nearby Hassan Borro barracks, Palestinians and Lebanese officers nearly opened fire over the handover.

Fisk adds that during the invasion Gur declared that Israel would fall back to the Christian enclaves as a border 'security belt': the strip that became Major Haddad's.

Musa al-Sadr travelled to Libya on 25 August (de Clerck and Malsagne) at the invitation of the Libyan government (Ménargues) and was never seen again; Hanf dates the disappearance to September. Beirut papers speculated about the Shah's secret police or Libyan intelligence. Fisk writes that he was almost certainly killed in Libya. The loss mobilised the Shi'a and later strengthened Amal.

Schools, hospitals and factories were destroyed in the new bombardment, and Lebanese gendarmes logged 2,000 impacts a day in Achrafieh. Hanf links it to the Camp David agreement reached a few days before.