The Northern Democratic Brigade is a Free Syrian Army unit that is closely allied to the Syrian Kurdish YPG and YPJ in Afrin Region since 2014. Led by Absi Taha, Alexander Khalil, and Alexander Alaa, it also joined the Syrian Democratic Forces (SDF) in November 2015. The initial members of the group originated from Jabal Zawiya in Idlib, and it has recruited Arabs from Idlib, Aleppo, and other cities in northern Syria since allying with the YPG. Since joining the SDF, the unit has begun to operate across much of northern and eastern Syria, participating in operations against anti-SDF Syrian opposition factions, the Islamic State of Iraq and the Levant, the Turkish Armed Forces, and the Syrian National Army.

The Syrian Democratic Forces (SDF) is a Kurdish-led coalition formed by ethnic militias and rebel groups, and serves as the official military wing of the Autonomous Administration of North and East Syria (AANES). The SDF is allied to and supplied by the United States–led CJTF–OIR international alliance. Founded in 10 October 2015, the SDF claims that its mission is fighting to create a secular, democratic and federalised Syria. The SDF is opposed by Turkey, who claims the group has direct links to the PKK, which it recognizes as a terrorist group.