The Six-Day War (حرب الأيام الستة, Ḥarb al‑Ayyam as‑Sitta or more commonly حرب 1967, Ḥarb 1967; מלחמת ששת הימים, Milhemet Sheshet Ha‑Yamim), also known as the 1967 Arab-Israeli War, the Third Arab-Israeli War, Six Days' War, an‑Naksah (The Setback), or the June War, was fought between Israel and Arab neighbors Egypt, Jordan, and Syria. The nations of Iraq, Saudi Arabia, Kuwait, and Algeria also contributed troops and arms to the Arab forces.

In May 1967, Egypt expelled the United Nations Emergency Force (UNEF) from the Sinai Peninsula, which had been stationed there since 1957 (following the 1956 Sinai invasion to allow for a free Suez Canal), to provide a peace-keeping buffer zone. In reaction to Israeli-Syrian tensions, Egypt amassed 1000 tanks and 100,000 soldiers on the border, closed the Straits of Tiran to all ships flying Israeli flags or carrying strategic materials, and called for unified Arab action against Israel. In response, on June 5, 1967, Israel launched a pre-emptive attack against Egypt's airforce. Jordan, which had signed a mutual defence treaty with Egypt on May 30, then attacked western Jerusalem and Netanya. "In May-June 1967 Eshkol's government did everything in its power to confine the confrontation to the Egyptian front. Eshkol and his colleagues took into account the possibility of some fighting on the Syrian front. But they wanted to avoid having a clash with Jordan and the inevitable complications of having to deal with the predominantly Palestinian population of the West Bank. The fighting on the eastern front was initiated by Jordan, not by Israel. King Hussein got carried along by a powerful current of Arab nationalism. On 30 May he flew to Cairo and signed a defense pact with Nasser. On 5 June, Jordan started shelling the Israeli side in Jerusalem. This could have been interpreted either as a salvo to uphold Jordanian honor or as a declaration of war. Eshkol decided to give King Hussein the benefit of the doubt. Through General Odd Bull, the Norwegian commander of UNTSO, he sent the following message the morning of 5 June: 'We shall not initiate any action whatsoever against Jordan. However, should Jordan open hostilities, we shall react with all our might, and the king will have to bear the full responsibility of the consequences.' King Hussein told General Bull that it was too late; the die was cast." Avi Shlaim, The Iron Wall: Israel and the Arab World, W. W. Norton & Company, 2000, ISBN 0393048160, pp. 243-244. At the war's end, Israel had gained control of the Sinai Peninsula, the Gaza Strip, the West Bank, eastern Jerusalem, and the Golan Heights. The results of the war affect the geopolitics of the region to this day.