The Yom Kippur War, also known as the Ramadan War, the October War, the 1973 Arab–Israeli War, or the Fourth Arab–Israeli War, was an armed conflict fought from October 6 to 25, 1973 between Israel and a coalition of Arab states led by Egypt and Syria. The majority of combat between the two sides took place in the Sinai Peninsula and the Golan Heights—both of which were occupied by Israel in 1967—with some fighting in African Egypt and northern Israel. Egypt's initial objective in the war was to seize a foothold on the eastern bank of the Suez Canal and subsequently leverage these gains to negotiate the return of the rest of the Israeli-occupied Sinai Peninsula.

The war began on October 6, 1973, when the Arab coalition jointly launched a surprise attack against Israel on the Jewish holy day of Yom Kippur, which had occurred during the 10th of the Islamic holy month of Ramadan in that year. Following the outbreak of hostilities, both the United States and the Soviet Union initiated massive resupply efforts to their respective allies during the war, which led to a near-confrontation between the two nuclear-armed superpowers.

Fighting commenced when Egyptian and Syrian forces crossed their corresponding ceasefire lines with Israel and invaded the Sinai Peninsula and the Golan Heights. Egyptian forces crossed the Suez Canal in Operation Badr and advanced into the Sinai Peninsula; the Syrians launched a coordinated attack on the Golan Heights to coincide with the Egyptian offensive and initially made gains into Israeli-held territory. After three days of heavy fighting, Israel halted the Egyptian offensive, resulting in a military stalemate on that front, and pushed the Syrians back to the pre-war ceasefire lines. The Israeli military then launched a four-day-long counter-offensive deep into Syria, and, within a week, Israeli artillery began to shell the outskirts of the Syrian capital of Damascus. Egyptian forces meanwhile pushed for two strategic mountain passes deeper within the Sinai Peninsula, but were repulsed, and Israeli forces counter-attacked by crossing the Suez Canal into Egypt and advancing towards Suez City. On October 22, an initial ceasefire brokered by the United Nations unravelled, with each side blaming the other for the breach. By October 24, the Israelis had improved their positions considerably and completed their encirclement of the Egyptian Third Army and Suez City, bringing them within 100 kilometres (62 mi) of the Egyptian capital of Cairo. This development led to dangerously heightened tensions between the United States and the Soviet Union (allied with Israel and with the Arab states, respectively) and a second ceasefire was imposed cooperatively on October 25, 1973, to officially end the war.

The Yom Kippur War had far-reaching implications; the Arab world had experienced humiliation in the lopsided rout of the Egyptian–Syrian–Jordanian alliance in 1967, but felt psychologically vindicated by early successes in the 1973 conflict. The Israelis recognized that, despite impressive operational and tactical achievements on the battlefield, there was no guarantee that they would always dominate the Arab states militarily, as they had done consistently throughout the First, Second and Third Arab–Israeli Wars; these changes paved the way for the Israeli–Palestinian peace process. The 1978 Camp David Accords that followed the war saw Israel return the entire Sinai Peninsula to Egypt and the subsequent 1979 Egyptian–Israeli peace treaty, which marked the first instance of an Arab country recognizing Israel as a legitimate state. Following the achievement of peace with Israel, Egypt continued its drift away from the Soviet Union and eventually left the Soviet sphere of influence entirely.