During 2015, there was a period of significantly increased movement of refugees and migrants into Europe. 1.3 million people came to the continent to request asylum, the most in a single year since World War II. They were mostly Syrians, but also included significant numbers from Afghanistan, Nigeria, Pakistan, Iraq, Eritrea, and the Balkans. The increase in asylum seekers has been attributed to factors such as the escalation of various wars in the Middle East and ISIL's territorial and military dominance in the region due to the Arab Winter, as well as Lebanon, Jordan, and Egypt ceasing to accept Syrian asylum seekers.

Refugees of the Syrian civil war are citizens and permanent residents of Syria who have fled the country throughout the Syrian civil war. The pre-war population of the Syrian Arab Republic was estimated at 22 million (2017), including permanent residents. Of that number, the United Nations (UN) identified 13.5 million (2016) as displaced persons, requiring humanitarian assistance. Of these, since the start of the Syrian civil war in 2011 more than six million (2016) were internally displaced, and around five million (2016) had crossed into other countries, seeking asylum or placed in Syrian refugee camps worldwide. It is often described as one of the largest refugee crises in history.