The Kataeb Party (lit. 'Battalions Party'), officially the Kataeb Party – Lebanese Social Democratic Party (Arabic: حزب الكتائب اللبنانية – الحزب الديمقراطي الاجتماعي اللبناني Ḥizb al-Katā'ib al-Lubnānīya), also known as the Phalangist Party, is a right-wing Christian political party in Lebanon founded by Pierre Gemayel in 1936.
The party and its paramilitary wings played a major role in the Lebanese Civil War (1975–1990), opposing Palestinian insurgency in South Lebanon as well as collaborating with Israel. The Phalangists were responsible for the Black Saturday massacre, the Tel al-Zaatar massacre, Ehden massacre, and the Karantina massacre. In 1982, Pierre's youngest son Bachir, the leader of the party's militia, was elected President, but was assassinated before he could take office. This led to Phalangist militiamen committing the infamous Sabra and Shatila massacre during the 1982 war, with support from the IDF.
Bachir was succeeded by his older brother Amine, who led the party through much of the war. In decline in the late 1980s and 1990s during the Syrian occupation of Lebanon, the party slowly re-emerged in the early 2000s and is currently part of the Lebanese opposition. The party currently holds 4 out of the 128 seats in the Lebanese Parliament.