List of largest refugee crises in the context of "Internally displaced persons"

On 24 February 2022, Russia invaded Ukraine, starting the largest and deadliest war in Europe since World War II. It is a major escalation of the war between the two countries that began in 2014. The fighting has caused hundreds of thousands of military casualties and tens of thousands of Ukrainian civilian casualties. As of 2025, Russian troops occupy about 20% of Ukraine. From a population of 41 million, about 8 million Ukrainians had been internally displaced and more than 8.2 million had fled the country by April 2023, creating Europe's largest refugee crisis since World War II.

In late 2021, Russia massed troops near Ukraine's borders and issued demands to the West, including a ban on Ukraine ever joining NATO. After repeatedly denying having plans to attack Ukraine, on 24 February 2022, Russian president Vladimir Putin announced a "special military operation", saying that it was to support the Russian-backed breakaway republics of Donetsk and Luhansk, whose paramilitary forces had been fighting Ukraine in the war in Donbas since 2014. Putin espoused irredentist and imperialist views challenging Ukraine's legitimacy as a state, baselessly claimed that the Ukrainian government were neo-Nazis committing genocide against the Russian minority in the Donbas, and said that Russia's goal was to "demilitarise and denazify" Ukraine. Russian air strikes and a ground invasion were launched on a northern front from Belarus towards the capital Kyiv, a southern front from occupied Crimea, and an eastern front from the Donbas towards Kharkiv. Ukraine enacted martial law, ordered a general mobilisation, and severed diplomatic relations with Russia.

The Ukrainian refugee crisis began with the Russian invasion of Ukraine in February 2022. As of September 2025, the UNHCR has recorded 5.7 million Ukrainian refugees around the world, with 90% of this figure residing in various European countries outside of Ukraine. Older reports by the International Organization for Migration in May 2022 show approximately eight million Ukrainians as internally displaced persons. By 20 March 2022, nearly one-quarter of Ukraine's total population had been displaced due to active military hostilities with Russia. About 90% of all Ukrainian refugees are women and children; by 24 March, more than half of all children in Ukraine had left their homes, of whom a quarter had left the country as well. Men between the ages of 18 and 60 have been banned from leaving the country under Ukrainian martial law, which came into force a few hours into Russia's first military offensive into Ukraine. This ongoing escalation of the Russo-Ukrainian War has caused the largest refugee crisis in the 21st century and the fourth-largest refugee crisis in modern history as a whole, with the highest refugee flight rate globally. It is also the first European refugee crisis since the Yugoslav Wars in the 1990s and the largest one to have occurred in Europe since World War II.

The vast majority of Ukrainian refugees initially entered neighbouring countries to the west of Ukraine (Poland, Slovakia, Hungary, Romania, and Moldova). Around three million of these people then moved further west to other European countries. As of May 2025, the UNHCR reports that the countries in which the largest numbers of Ukrainians had applied for asylum, or other temporary protection, are Germany (1.2 million), Poland (1 million), and the Czech Republic (0.4 million). As of September 2022, Human Rights Watch has documented that Ukrainian civilians, particularly children, have been forcibly transferred to Russia. The OHCHR has corroborated this claim, stating that "There have been credible allegations of forced transfers of unaccompanied children to Russian-occupied territory, or to the Russian Federation itself." The United States Department of State estimated that at least 900,000 Ukrainian citizens (including children) were forcibly transferred to Russia in the first six months after the invasion. Around the same time in late 2022, more than 4.5 million Ukrainians had returned to Ukraine, owing to the withdrawal of Russian troops from all fronts but the Donbas and parts of southern Ukraine.

Refugees of the Syrian civil war are citizens and permanent residents of Syria who fled the country in the course of the Syrian civil war. The pre-war population of Syria was estimated at 22 million (2017), including permanent residents. Of that number, the United Nations (UN) identified 13.5 million (2016) as displaced persons in need of humanitarian assistance. Since the start of the Syrian civil war in 2011 more than six million (2016) were internally displaced, and around five million (2016) crossed into other countries, seeking asylum or placement in Syrian refugee camps. It is believed to be one of the world's largest refugee crises.

Armed revolts started across Syria in 2011 when security forces launched a violent campaign to halt nation-wide protests. This led to the establishment of resistance militias and the outbreak of a civil war. Assaults on civilian areas by the Syrian Armed Forces resulted in the forced displacement of millions of Syrians and a full-blown refugee crisis. The Regional Refugee and Resilience Plan (3RP) was established in 2015 as a coordination platform including neighboring countries except Israel. By 2016, various nations had made pledges to the United Nations High Commissioner for Refugees (UNHCR) to permanently resettle 170,000 registered refugees. Syrian refugees have contributed to the European migrant crisis, with the UNHCR receiving almost one million asylum applicants in Europe by August 2017. Turkey was the largest host country of registered refugees, with 3.6 million Syrian refugees in 2019, 3.3 million in 2023, and almost 3 million at the time of the Fall of the Assad regime in December 2024.