Al-Nusra Front or Jabhat al-Nusra or Jabhat Nusrat Ahl al-Sham, also known as Front for the Conquest of the Levant, and also later known as Jabhat Fatah al-Sham was a Salafi-jihadist organization that fought against Ba'athist regime forces in the Syrian Civil War. Its aim was to overthrow president Bashar al-Assad and establish an Islamic state ruled by Sharia law in Syria.

Formed in 2012, in November of that year The Washington Post described al-Nusra as "the most aggressive and successful" of the rebel forces. While secular and pro-democratic rebel groups of the Syrian Revolution such as the Free Syrian Army were focused on ending the decades-long reign of the Assad family, al-Nusra Front also sought the unification of Islamist forces in a post-Assad Syria, anticipating a new stage of the civil war. It denounced the international assistance in support of the Syrian opposition as "imperialism"; viewing it as a long-term threat to its Islamist goals in Syria.

In December 2012, the US Department of State designated it as a "foreign terrorist organization". In April 2013, Al-Nusra Front was publicly confirmed as the official Syrian affiliate of al-Qaeda, after Emir Ayman al-Zawahiri rejected the forced merger attempted by Abu Bakr al-Baghdadi and ordered the dissolution of newly-formed Islamic State of Iraq and Levant. In March 2015, the militia joined other Syrian Islamist groups to form a joint command center called the Army of Conquest. In July 2016, al-Nusra formally re-designated itself from Jabhat al-Nusra to Jabhat Fatah al-Sham ("Front for the Conquest of the Levant") and officially announced that it was breaking ties with Al-Qaeda.

The announcement caused defections of senior Al-Nusra commanders and criticism from al-Qaeda ranks, provoking a harsh rebuke from Ayman al-Zawahiri, who denounced it as an "act of disobedience". On 28 January 2017, following violent clashes with Ahrar al-Sham and other rebel groups, Jabhat Fatah al-Sham (JFS) merged with four other groups to form Hayat Tahrir al-Sham (HTS), a new Sunni Islamist militant group. Tahrir al-Sham denies any links to the al-Qaeda network and said in a statement that the group is "an independent entity and not an extension of previous organizations or factions". Mutual hostilities eventually deteriorated into one of violent confrontations, with Al-Nusra commander Sami al-Oraydi accusing HTS of adopting nationalist doctrines. Sami al-Oraydi, alongside other Al-Qaeda loyalists like Abu Humam al-Shami, Abu Julaybib and others, mobilised Al-Qaeda personnel in northwestern Syria to establish an anti-HTS front in north-western Syria, eventually forming Hurras al-Din on 27 February 2018.

From 2012 to 2013, al-Nusra Front's full name was the "Victory Front for the People of the Levant by the Mujahideen of the Levant on the Fields of Jihad" (Arabic: جبهة النصرة لأهل الشام من مجاهدين الشام في ساحات الجهاد, romanized: Jabhat an-Nuṣrāh li-ahli ash-Shām min Mujāhidīn ash-Shām fī Sahat al-Jihād).

The al-Nusra Front was estimated to be primarily made up of Syrian jihadists. Its goals were to overthrow Bashar al-Assad's government in Syria and to create an Islamic emirate under sharia law, with an emphasis from an early stage on focusing on the "near enemy" of the Syrian regime rather than on global jihad. Syrian members of the group claimed that they are fighting only the Assad regime and would not attack Western states; while the official policy of the group was to regard the United States and Israel as enemies of Islam, and to warn against Western intervention in Syria, al-Nusra Front leader Julani stated that "We are only here to accomplish one mission, to fight the regime and its agents on the ground, including Hezbollah and others". In early 2014, Sami al-Oraydi, a top sharia official in the group, acknowledged that it is influenced by the teachings of al-Qaeda member Abu Musab al-Suri. The strategies derived from Abu Musab's guidelines included providing services to people, avoiding being seen as extremists, maintaining strong relationships with local communities and other fighting groups, and putting the focus on fighting the government.

The tactics of al-Nusra Front differed markedly from those of rival jihadist group ISIL; whereas ISIL has alienated local populations by demanding their allegiance and carrying out beheadings, al-Nusra Front cooperated with other militant groups and declined to impose sharia law where there has been opposition. Analysts have noted this could have given the al-Nusra Front a greater long-term advantage.

In early 2015, al-Qaeda leader Ayman al-Zawahiri instructed al-Nusra Front leader Julani to pursue the following five goals: