1978 South Lebanon conflict in the context of "Blue Line (Lebanon)"

The Blue Line is a demarcation line dividing Lebanon from Israel and the Golan Heights. It was published by the United Nations on 7 June 2000 for the purposes of determining whether Israel had fully withdrawn from Lebanon. It has been described as "temporary" and "not a border, but a “line of withdrawal”. It is the subject of an ongoing border dispute between Israel, Lebanon, and Hezbollah.

On 19 March 1978, the United Nations Security Council adopted Resolutions 425 and 426 calling for Israeli withdrawal from Lebanon following its recent invasion and to ensure that the government of Lebanon restores effective authority in the area to the border. The United Nations Security Council and NATO set up the United Nations Interim Force in Lebanon (UNIFIL) as a peacekeeping force to supervise the situation in Southern Lebanon.

The Shebaa Farms, also spelled Sheba'a Farms (Arabic: مزارع شبعا, Mazāri' Šib‘ā; Hebrew: חוות שבעא Havot Sheba‘a), also known as Mount Dov (Hebrew: הר דב, romanized: Har Dov), is a strip of land on the Lebanese–Syrian border that is currently occupied by Israel. Lebanon claims the Shebaa Farms as its own territory, and Syria agrees with this position. Israel claims it is part of the Golan Heights, Syrian territory that it has occupied since 1967 and effectively annexed in 1981. This dispute plays a significant role in contemporary Israel–Lebanon relations.

The territory is named for the farms within it which were historically tended by the inhabitants of the Lebanese town of Shebaa. It is about 11 kilometres (7 mi) long and 2.5 kilometres (2 mi) wide. The French Mandate for Syria and the Lebanon administration did not demarcate the border between Lebanon and Syria, nor was this done later by Lebanese and Syrian governments. Documents from the 1920s and 1930s indicate that inhabitants paid taxes to the Lebanese government. From the early 1950s to Israel's occupation of the Golan Heights in the Six-Day War, Syria was the de facto ruling power. In 1978 Israel invaded and occupied Southern Lebanon. In 1981, the Golan Heights, including the Shebaa Farms, were annexed by Israel, a move not recognized by the international community. Israel considers it part of the Golan Heights and continues to hold it, along with the Golan, under military occupation.

The United Nations Interim Force in Lebanon (Arabic: قوة الأمم المتحدة المؤقتة في لبنان; Hebrew: כוח האו"ם הזמני בלבנון), or UNIFIL (Arabic: يونيفيل; Hebrew: יוניפי״ל) is a United Nations peacekeeping mission established on 19 March 1978 by United Nations Security Council Resolutions 425 and 426, and several further resolutions in 2006 to confirm Hezbollah demilitarisation, support Lebanese army operations against insurgents and weapon smuggling, and confirming Israeli withdrawal from Lebanon, in order to ensure that the government of Lebanon would restore its effective authority in the area. The 1978 South Lebanon conflict came in the context of Palestinian insurgency in South Lebanon and the Lebanese Civil War.

The mandate had to be adjusted due to the Israeli invasion of Lebanon in 1982 and after the Israeli withdrawal from Lebanon in 2000. Following the 2006 Lebanon War, the United Nations Security Council enhanced UNIFIL and added additional tasks to the mandate such as aiding displaced persons.

The 1982 Lebanon War, also called the Second Israeli invasion of Lebanon, began on 6 June 1982, when Israel invaded southern Lebanon. The invasion followed a series of attacks and counter-attacks between the Palestine Liberation Organization (PLO) operating in southern Lebanon and the Israel Defense Forces (IDF), which had caused civilian casualties on both sides of the border. The Israeli military operation, codenamed Operation Peace for Galilee, was launched after gunmen from the Abu Nidal Organization attempted to assassinate Shlomo Argov, Israel's ambassador to the United Kingdom. Israeli prime minister Menachem Begin blamed the PLO, using the incident as a casus belli. It was the second invasion of Lebanon by Israel, following the 1978 South Lebanon conflict.

The Israelis sought to end Palestinian attacks from Lebanon, destroy the Palestine Liberation Organization (PLO) in the country, and install a pro-Israel Maronite Christian government. Israeli forces attacked and overran PLO positions in southern Lebanon and briefly clashed with the Syrian Army, who occupied most of the country's northeast. The Israeli military, together with the South Lebanon Army, seized control of the southern half of Lebanon and laid siege to the capital Beirut. The Lebanese Forces however, despite their clandestine alliance with Israel, refused to participate in the war against the PLO as their leader Bachir Gemayel viewed any direct involvement as assisting an invading army. Surrounded in West Beirut and subjected to heavy Israeli bombardment, the PLO and their allies negotiated a ceasefire with the aid of United States special envoy Philip Habib. The PLO, led by Yasser Arafat, were evacuated from Lebanon, overseen by a multinational peacekeeping force. By expelling the PLO, removing Syrian influence over Lebanon, and installing a pro-Israeli Christian government led by President Bachir Gemayel, the Israeli government hoped to sign a treaty that would give Israel "forty years of peace".

The South Lebanon conflict was an armed conflict that took place in Israeli-occupied southern Lebanon from 1982 or 1985 until Israel's withdrawal in 2000. Hezbollah, along with other Shia Muslim and left-wing guerrillas, fought against Israel and its ally, the Catholic Christian-dominated South Lebanon Army (SLA). The SLA was supported militarily and logistically by the Israel Defense Forces (IDF) and operated under the jurisdiction of the Israeli-backed South Lebanon provisional administration, which succeeded the earlier Israeli-backed Free Lebanon State. Israel officially names the conflict the Security Zone in Lebanon Campaign and deems it to have begun on 30 September 1982, after the end of its "Operation Peace for Galilee". It can also be seen as an extension of the Lebanese Civil War (1975–1990).

Israel invaded Lebanon in 1978 and in 1982, to end the Palestinian insurgency in South Lebanon and support Lebanese Maronite Christians in the Lebanese Civil War. The 1982 invasion resulted in the Palestine Liberation Organization (PLO) leaving Lebanon and marked the beginning of Israeli occupation. Militant groups began attacking Israeli forces in southern Lebanon in September 1982. Amid rising casualties from guerrilla attacks, the IDF retreated south of the Awali river on 3 September 1983. The IDF began a phased withdrawal from Lebanon in February 1985. It withdrew to a "security zone" along the border on 29 April, and most IDF troops withdrew from the "security zone" on 10 June. A small number of IDF soldiers remained in the zone to support the SLA. Throughout its existence, there were about 1,500 IDF and 2,500 SLA troops in the "security zone" at any given time.

The Israeli–Lebanese conflict, or the South Lebanon conflict, is a long-running conflict involving Israel, Lebanon-based paramilitary groups, and sometimes Syria. The conflict peaked during the Lebanese Civil War. In response to Palestinian attacks from Lebanon, Israel invaded the country in 1978 and again in 1982. After this it occupied southern Lebanon until 2000, while fighting a guerrilla conflict against Shia paramilitaries. After Israel's withdrawal, Hezbollah attacks sparked the 2006 Lebanon War. A new period of conflict began in 2023, leading to the 2024 Israeli invasion of Lebanon.

The Palestine Liberation Organization (PLO) recruited militants in Lebanon from among the Palestinian refugees who had been expelled or fled after the creation of Israel in 1948. After the PLO leadership and its Fatah brigade were expelled from Jordan in 1970–71 for fomenting a revolt, they entered southern Lebanon, resulting in an increase of internal and cross-border violence. Meanwhile, demographic tensions over the Lebanese National Pact led to the Lebanese Civil War (1975–1990). PLO actions were one of the key factors in the eruption of the Lebanese Civil War and its bitter battles with Lebanese factions caused foreign intervention. Israel's 1978 invasion of Lebanon pushed the PLO north of the Litani River, but the PLO continued their campaign against Israel. This invasion led to the deployment of United Nations peacekeepers in southern Lebanon. Israel invaded Lebanon again in 1982 and, in alliance with the Christian Lebanese Forces, forcibly expelled the PLO. In 1983, Israel and Lebanon signed the May 17 Agreement providing a framework for the establishment of normal bilateral relations between the two countries, but relations were disrupted with takeover of Shia and Druze militias in early 1984. Israel withdrew from most of Lebanon in 1985, but kept control of a 19-kilometre (12-mile) security buffer zone, held with the aid of proxy militants in the South Lebanon Army (SLA).