Palestinian fedayeen (from the Arabic fidā'ī, plural fidā'iyūn, فدائيون) are militants or guerrillas of a nationalist orientation from among the Palestinian people. Most Palestinians consider the fedayeen to be "freedom fighters", while most Israelis consider them to be "terrorists".
Considered symbols of the Palestinian national movement, the Palestinian fedayeen drew inspiration from guerrilla movements in Vietnam, China, Algeria and Latin America. The ideology of the Palestinian fedayeen was mainly left-wing nationalist, socialist or communist, and their proclaimed purpose was to defeat Zionism, claim Palestine and establish it as "a secular, democratic, nonsectarian state". The meaning of secular, democratic and non-sectarian, however, greatly diverged among fedayeen factions.
Emerging from among the Palestinian refugees who fled or were expelled from their villages as a result of the 1948 Arab–Israeli War, in the mid-1950s the fedayeen began mounting cross-border operations into Israel from Syria, Egypt and Jordan. The earliest infiltrations were often to access the land's agricultural products they had lost as a result of the war, or to attack Israeli military, and sometimes civilian targets. The Gaza Strip, the sole territory of the All-Palestine Protectorate—a Palestinian state declared in October 1948—became the focal point of the Palestinian fedayeen activity. Fedayeen attacks were directed on Gaza and Sinai borders with Israel, and as a result Israel undertook retaliatory actions, targeting the fedayeen that also often targeted the citizens of their host countries, which in turn provoked more attacks.
Fedayeen actions were cited by Israel as one of the reasons for its launching of the Sinai Campaign of 1956, the 1967 War, and the 1978 and 1982 invasions of Lebanon. Palestinian fedayeen groups were united under the umbrella the Palestine Liberation Organization after the defeat of the Arab armies in the 1967 Six-Day War, though each group retained its own leader and independent armed forces.