Palestinian refugees are citizens of Mandatory Palestine, and their descendants, who fled or were expelled from their country over the course of the 1947–49 Palestine war (1948 Palestinian exodus) and the Six-Day War (1967 Palestinian exodus). Most Palestinian refugees live in or near 68 Palestinian refugee camps across Jordan, Lebanon, Syria, the West Bank and the Gaza Strip. In 2019 more than 5.6 million Palestinian refugees were registered with the United Nations.

The term originally referred to both Arabs and Jews whose normal place of residence had been in Mandatory Palestine but were displaced and lost their livelihoods as a result of the 1948 Palestine war. In 1949, the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) defined Palestinian refugees to refer to the original "Palestine refugees" as well as their patrilineal descendants. However, UNRWA's assistance is limited to Palestine refugees residing in UNRWA's areas of operation in the Palestinian Territories, Lebanon, Jordan and Syria.As of 2019, more than 5.6 million Palestinians were registered with UNRWA as refugees, of which more than 1.5 million live in UNRWA-run camps. The term "Palestine refugee" does not include internally displaced Palestinians, who became Israeli citizens and neither displaced Palestinian Jews. According to some estimates, as many as 1,050,000–1,380,000 people, who descend from displaced people of Mandatory Palestine are not registered under UNRWA and neither UNHCR mandates.

During the 1948 Palestine War, around 700,000 Palestinian Arabs or 85% of the total population in what became Israel fled or were expelled from their homes, to the West Bank, the Gaza Strip, and to the countries of Lebanon, Syria and Jordan. They, and their descendants who are also entitled to registration, are assisted by UNWRA in 59 registered camps, ten of which were established in the aftermath of the Six-Day War in 1967 to cope with the new wave of displaced Palestinians. They are also the world's oldest unsettled refugee population, having been under the ongoing governance of Arab states following the 1948 Arab–Israeli War, the refugee populations of the West Bank under Israeli governance since the Six-Day War and Palestinian administration since 1994, and the Gaza Strip administered by the Islamic Resistance Movement (Hamas) since 2007. Citizenship or legal residency in host countries is denied in Lebanon where the absorption of Palestinians would upset a delicate confessional balance, but available in Jordan where by 2009 over 90% of UNWRA-registered Palestinian refugees have acquired full citizenship rights.On 11 December 1948, the General Assembly of the United Nations (UNGA) adopted Resolution 194 which affirmed the Palestinians right to return to their homes.