1948 Palestinian expulsion and flight

In 1948, more than 700000 Palestinian Arabs – about half of prewar Mandatory Palestine's Arab population – fled from their homes or were expelled by Zionist militias and, later, the Israeli army during the 1948 Palestine war, following the Partition Plan for Palestine. The expulsion and flight was a central component of the fracturing, dispossession, and displacement of Palestinian society, known as the Nakba. Dozens of massacres were conducted by Israeli military forces and between 400 and 600 Palestinian villages were destroyed. Village wells were poisoned in a biological warfare programme and properties were looted to prevent Palestinian refugees from returning. Other sites were subject to Hebraization of Palestinian place names. These activities were not necessarily limited to the year 1948.

The precise number of Palestinian refugees, many of whom settled in Palestinian refugee camps in neighboring states, is a matter of dispute. Around 80 percent of the Arab inhabitants of what became Israel (half of the Arab total population of Mandatory Palestine) left or were expelled from their homes. About 250000–300000 Palestinians fled or were expelled during the 1947–1948 civil war in Mandatory Palestine, before the Israeli Declaration of Independence in May 1948, a fact which was named as a casus belli for the entry of the Arab League into the country, sparking the 1948 Arab–Israeli War.

The causes of the 1948 Palestinian exodus are also a subject of fundamental disagreement among historians. Factors involved in the exodus include Jewish military advances, destruction of Arab villages, psychological warfare, fears of another massacre by Zionist militias after the Deir Yassin massacre,^{: 239–240} which caused many to leave out of panic, direct expulsion orders by Israeli authorities, the demoralizing impact of wealthier classes fleeing, the typhus epidemic in some areas caused by Israeli well-poisoning, collapse in Palestinian leadership and Arab evacuation orders, and a disinclination to live under Jewish control.

Later, a series of land and property laws passed by the first Israeli government prevented Arabs who had left from returning to their homes or claiming their property. They and many of their descendants remain refugees. The expulsion of the Palestinians has since been described by some historians as ethnic cleansing, while others dispute this charge. Nevertheless, the existence of the so-called Law of Return allowing for immigration and naturalization of any Jewish person and their family to Israel, while a Palestinian right of return has been denied, has been cited as an evidence for the charge that Israel practices apartheid.

The status of the refugees, and in particular whether Israel will allow them the right to return to their homes, or compensate them, are key issues in the ongoing Israeli–Palestinian conflict. The events of 1948 are commemorated by Palestinians both in the Palestinian territories and elsewhere on 15 May, a date known as Nakba Day.