Hay'at Tahrir al-Sham (HTS) was a Sunni Islamist political organisation and paramilitary group involved in the Syrian civil war. It was formed on 28 January 2017 as a merger of several armed groups: Jaysh al-Ahrar (an Ahrar al-Sham faction), Jabhat Fateh al-Sham (JFS), Ansar al-Din Front, Jaysh al-Sunna, Liwa al-Haqq and the Nour al-Din al-Zenki Movement. The unification process was held under the initiative of Abu Jaber Sheikh, an Islamist militant commander who had been the second emir of Ahrar al-Sham. HTS, along with other Syrian opposition groups, launched an offensive that led to the fall of the Assad regime on 8 December 2024.
Proclaiming the nascent organisation as "a new stage in the life of the blessed revolution", Abu Jaber Sheikh urged all factions of the Syrian opposition to unite under its Islamic leadership and wage a "popular jihad" to achieve the objectives of the Syrian revolution, which he characterised as the ouster of the Ba'athist regime and Hezbollah militants from Syrian territories, and the formation of an Islamic government. After the announcement, additional groups and individuals joined. The merged group has been primarily led by Jabhat Fatah al-Sham and former Ahrar al-Sham leaders, although the High Command also has representation from other groups. The Nour al-Din al-Zenki Movement split from Tahrir al-Sham in July 2017, and the Ansar al-Din Front in 2018.