Hashim al-Shaykh (Arabic: هاشم الشيخ), also known by his nom de guerre Abu Jaber Shaykh (Arabic: أبو جابر الشيخ) is a rebel commander during the Syrian Civil War who is a senior leader of Tahrir al-Sham. He had reportedly resigned from his position in Ahrar al-Sham where he served as a senior commander to help command and direct the merger. Abu Jaber is a Sunni Muslim with a Salafist jihadist ideology, which is reflected in the ideology of the group he leads.
Abu Jaber received a bachelor's degree in mechanical engineering at the University of Aleppo. After this, he worked at the Defence Factories near as-Safira. His Salafist activities led to him being arrested by the Syrian government several times. In 2005, he was imprisoned in the Sednaya Prison, infamous for holding a number of other Salafist prisoners who were later released.
On 25 September 2011, during the early phase of the Syrian Civil War, Abu Jaber was released from Sednaya Prison among a number of other Salafist and jihadist political prisoners. He joined Harakat Fajr ash-Sham al-Islamiya and fought alongside the al-Nusra Front. He led a subgroup within Harakat Fajr ash-Sham al-Islamiya called the Mus‘ab ibn 'Umair Battalion, which became one of the founding members of Ahrar al-Sham. Abu Jaber is one of the three surviving founding figures of Ahrar al-Sham.
In September 2014, the founder and commander of Ahrar al-Sham, Hassan Aboud, was assassinated along with 45 of his fighters in a bombing in the Idlib Governorate. Abu Jaber replaced his position and became the overall commander of Ahrar al-Sham. He resigned and was replaced by Muhannad al-Masri (Abu Yahya) in September 2015. An Ahrar al-Sham spokesman described Abu Jaber's leadership as the "hardest" period of the group.
On 15 February 2016, during the northern Aleppo offensive, 8 rebel factions pledged allegiance to Abu Jaber and established the Army of Aleppo to fight the Syrian Armed Forces and the Syrian Democratic Forces, including the Army of Revolutionaries.