1948 Palestinian expulsion and flight

In the 1948 Palestine war, more than 700,000 Palestinian Arabs – about half of Mandatory Palestine's predominantly Arab population – fled from their homes or were expelled. Expulsions and attacks against Palestinians were carried out by the Zionist paramilitaries Haganah, Irgun, and Lehi, which merged to become the Israel Defense Forces after the establishment of Israel part way through the war. The expulsion and flight was a central component of the fracturing, dispossession, and displacement of Palestinian society, known as the Nakba. Dozens of massacres targeting Arabs 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.

The precise number of Palestinian refugees, many of whom settled in Palestinian refugee camps in neighboring states, is a matter of dispute, although the number is around 700,000, being approximately 80 percent of the Arab inhabitants of what became Israel. About 250,000–300,000 Palestinians fled or were expelled during the 1947–1948 civil war in Mandatory Palestine, before the termination of the British Mandate on 14 May 1948. The desire to prevent the collapse of the Palestinians and to avoid more refugees were some of the reasons for the entry of the Arab League into the country, which began the 1948 Arab–Israeli War.

Although the causes of the 1948 Palestinian exodus remain a significantly controversial topic in public and political discourse, with a prominent amount of denialism regarding the responsibility of Israeli/Yishuv forces, most scholarship today agrees that expulsions and violence, and the fear thereof, were the primary causes. Scholars widely describe the event as ethnic cleansing, although some disagree. Factors involved in the exodus include direct expulsions by Israeli forces, destruction of Arab villages, psychological warfare including terrorism, massacres such as the widely publicized Deir Yassin massacre^{: 239–240} which caused many to flee out of fear, crop burning, typhoid epidemics in some areas caused by Israeli well-poisoning, and the collapse of Palestinian leadership including the demoralizing impact of wealthier classes fleeing.

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 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 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.