The siege of Koban was launched by the Islamic State of Iraq and the Levant on 13 September 2014, in order to capture the Koban Canton and its main city of Koban (also known as Koban or Ayn al-Arab) in northern Syria, in the de facto autonomous region of Rojava.

By 2 October 2014, the Islamic State succeeded in capturing 350 Kurdish villages and towns in the vicinity of Koban, generating a wave of some 300,000 Kurdish refugees, who fled across the border into Turkey's anlurfa Province. By January 2015, this had risen to 400,000. The Kurdish People's Protection Units (YPG) and some Free Syrian Army (FSA) factions (under the Euphrates Volcano joint operations room), Peshmerga of the Kurdistan Regional Government, and American and US-allied Arab militaries' airstrikes began to recapture Kobane.On 26 January 2015, the YPG and its allies, backed by the continued US-led airstrikes, began to retake the city, driving ISIL into a steady retreat. The city of Koban was fully recaptured on 27 January; however, most of the remaining villages in the Koban Canton remained under ISIL control. The YPG and its allies then made rapid advances in rural Koban, with ISIL withdrawing 25 km from the city of Koban by 2 February. By late April 2015, ISIL had lost almost all of the villages it had captured in the Canton, but maintained control of a few dozen villages it seized in the northwestern part of the Raqqa Governorate. In late June 2015, ISIL launched a new offensive against the city, killing at least 233 civilians, but were quickly driven back.

The battle for Koban was considered a turning point in the war against Islamic State.

The Islamic State (IS; official name since June 2014), at times known as the Islamic State of Iraq and the Levant (ISIL; ) or the Islamic State of Iraq and Syria (ISIS; ) and also referred to by its Arabic-language acronym Daesh (داعش, Dāʿish, IPA: [ˈdaːʕɪʃ]), is an Islamist militant jihadist group and former unrecognized quasi-state that follows a Salafi jihadist doctrine based on the Sunni branch of Islam. It was founded by Abu Musab al-Zarqawi in 1999 and gained global prominence in 2014, when it drove Iraqi security forces out of key cities during the Anbar campaign, which was followed by its capture of Mosul and the Sinjar massacre.ISIL originated in 1999, pledged allegiance to Al-Qaeda, and participated in the Iraqi insurgency following the 2003 invasion of Iraq by a multi-national coalition led by the United States. In June 2014, the group proclaimed itself to be a worldwide caliphate and began referring to itself as the Islamic State (الدولة الإسلامية, ad-Dawlah al-Islāmiyah). As a caliphate, it claimed religious, political, and military authority over all Muslims worldwide. Its adoption of the name "Islamic State" and its idea of a caliphate have been criticised, with the United Nations, various governments, and mainstream Muslim groups rejecting its statehood and legitimacy. In Syria, the group conducted ground attacks against both Syrian government forces and Syrian opposition factions; by December 2015, it held an area that contained an estimated eight to twelve million people and stretched from western Iraq to eastern Syria, where it enforced its interpretation of Islamic law. ISIL was estimated at the time to have an annual budget of more than US$1 billion and more than 30,000 fighters.In mid-2014, an international military coalition led by the United States intervened against ISIL in Syria as well as in Iraq with an airstrike campaign, in addition to supplying advisors, weapons, training, and supplies to ISIL's enemies in the Iraqi Armed Forces and the Syrian Democratic Forces. This campaign reinvigorated the latter two forces and damaged ISIL, killing tens of thousands of its fighters and reducing its financial and military infrastructure. The American-led intervention was followed by a smaller-scale Russian military intervention exclusively in Syria, in which ISIL lost thousands of more fighters to airstrikes, cruise missile attacks, and other Russian military activities, and had its financial base further degraded. In July 2017, the group lost control of its largest city, Mosul, to the Iraqi military, followed by the loss of its de facto political capital of Raqqa to the Syrian Democratic Forces. By December 2017, ISIL controlled just 2% of its maximum territory (achieved in May 2015). In December 2017, Iraqi forces had driven the last remnants of the group underground, three years after it had captured about a third of Iraq's territory. By March 2019, ISIL lost one of their last significant territories in the Middle East in the Deir ez-Zor campaign, and effectively surrendered their "tent city" and pockets in Al-Baghuz Fawqani to the Syrian Democratic Forces after the Battle of Baghuz Fawqani.The group has been designated as a terrorist organisation by the United Nations. It is well known for its videos of beheadings and other types of executions of both soldiers and civilians, including journalists and aid workers, as well as its destruction of cultural heritage sites. The international community holds ISIL responsible for committing massive human rights abuses, genocide, war crimes, and crimes against humanity. The group committed genocide against Yazidis and against Christians on a historic scale in northern Iraq and Syria, and systematically persecuted Shia Muslims during its rule. In October 2019, ISIL media announced that Abu Ibrahim al-Hashimi al-Qurashi had become the new leader of the group after Abu Bakr al-Baghdadi, the group's previous leader since 2013, died during an American military operation after detonating his suicide vest in Barisha, Syria. ISIL has also had a presence outside of the Middle East through its various "provinces" and affiliates, and has had a notable militant presence outside of the Arab world, predominantly in countries with significant or majority Muslim populations such as Nigeria, Cameroon, Chad, and Niger (West Africa Province); Afghanistan and Pakistan (Khorasan Province); as well as in countries with relatively low Muslim minority populations such as the Philippines (East Asia Province), the Democratic Republic of the Congo (Central Africa Province), and the Caucasus states (Caucasus Province).