The 1948 Palestinian exodus, known in Arabic as the Nakba (Arabic: النكبة‎, an-Nakbah, lit. "disaster", "catastrophe", or "cataclysm"), occurred when approximately 711,000 to 725,000 Palestinian Arabs left, fled or were expelled from their homes, during the 1948 Arab-Israeli War and the Civil War that preceded it. The exact number of refugees is a matter of dispute. The causes remain the subject of fundamental disagreement between Arabs and Israelis.

Nur-eldeen Masalha writes that over 80 percent of the Arab inhabitants left their towns and villages in 1948, while Rashid Khalidi puts the percentage at 50. Factors involved in the flight include Jewish military advances, attacks against Arab villages and fears of massacre after Deir Yassin, which caused many to leave out of panic; expulsion orders by Zionist authorities; the voluntary self-removal of the wealthier classes, the collapse in Palestinian leadership, and an unwillingness to live under Jewish control,. Later, a series of laws passed by the first Israeli government prevented them from returning to their homes, or claiming their property. They and many of their descendants remain refugees. Later in the war, Palestinians were expelled as part of Plan Dalet. The expulsion of the Palestinians has since been described by some historians as ethnic cleansing, while others dispute this charge.