There have been numerous reports of chemical weapons attacks in the Syrian Civil War, beginning in 2012, and corroborated by national governments, the United Nations (UN), the Organisation for the Prohibition of Chemical Weapons (OPCW), Human Rights Watch (HRW), and media organizations. The attacks occurred in different areas of Syria, including Khan al-Assal, Jobar, Saraqib, Ashrafiyat Sahnaya, Kafr Zita, Talmenes, Sarmin and Douma. The deadliest attacks were the August 2013 sarin attack in Ghouta, the April 2017 sarin attack in Khan Shaykhun and April 2018 Douma chemical attacks. The most common agent used is chlorine, with sarin and sulphur mustard also reported. Almost half of the attacks between 2014 and 2018 were delivered via aircraft and less than a quarter were delivered from the ground, with the remaining attacks having an undetermined method of delivery. Since the start of uprisings across Syria in 2011, Syrian Arab Armed Forces and pro-Assad paramilitary forces have been implicated in more than 300 chemical attacks in Syria.

The Khan Shaykhun chemical attack took place on 4 April 2017 on the town of Khan Shaykhun in the Idlib Governorate of Syria. The town was reported to have been struck by an airstrike by government forces followed by massive civilian chemical poisoning. The release of a toxic gas, which included sarin, or a similar substance, killed at least 89 people and injured more than 541, according to the opposition Idlib Health Directorate. The attack was the deadliest use of chemical weapons in the Syrian civil war since the Ghouta chemical attack in 2013.