The Suez Crisis, also referred to as the Tripartite Aggression or Suez War (Arabic: أزمة السويس – العدوان الثلاثي‎ ʾAzmat al-Sūwais / al-ʿUdwān al-Thulāthī; French: Crise du canal de Suez; Hebrew: מבצע קדש‎ Mivtza' Kadesh "Operation Kadesh," or מלחמת סיני Milẖemet Sinai, "Sinai War"), was a diplomatic and military confrontation in late 1956 between Egypt on one side, and Britain, France and Israel on the other, with the United States, the Soviet Union and the United Nations playing major roles in forcing Britain, France and Israel to withdraw.

Less than a day after Israel invaded Egypt, Britain and France issued a joint ultimatum to Egypt and Israel, and then began to bomb Cairo. Despite the denials of the Israeli, British and French governments, evidence began to emerge that the invasion of Egypt had been planned beforehand by the three powers. Anglo-French forces withdrew before the end of the year, but Israeli forces remained until March 1957, prolonging the crisis. In April, the canal was fully reopened to shipping, but other repercussions followed.

Suez (Arabic: السويس‎ as Suwais, Egyptian Arabic: [esseˈweːs]) is a seaport city (population ca. 497,000) in north-eastern Egypt, located on the north coast of the Gulf of Suez (a branch of the Red Sea), near the southern terminus of the Suez Canal, having the same boundaries as Suez governorate. It has three harbors, Adabya, Ain Sokhna and Port Tawfiq, and extensive port facilities. Together they form a metropolitan area. Railway lines and highways connect the city with Cairo, Port Said, and Ismailia. Suez has a petrochemical plant, and its oil refineries have pipelines carrying the finished product to Cairo.

In the 7th-century CE a town named "Kolzum" stood just north of the site of present-day Suez and served as eastern terminus of a canal built by Amr ibn al-'As linking the Nile River and the Red Sea. Kolzum's trade fell following the closure of the canal in 770 by the second Abbasid caliph al-Mansur to prevent his enemies in Arabia from accessing supplies from Egypt and the lands north of it. Nonetheless, the town benefited from the trade that remained between Egypt and Arabia. By 780 al-Mansur's successor al-Mahdi restored part of the canal. The Qarmatians led by Hasan ibn Ahmad defeated a Fatimid army headed by Gawhar al-Siqilli at Kolzum in 971 and thereby captured the town. Following his defeat in Cairo by al-Siqilli at the end of that year, Hasan and his forces retreated to Arabia via Kolzum. Suez was situated nearby and served as a source of drinking water for Kolzum according to Arab traveler al-Muqaddasi who visited in 986.

Robert Anthony Eden, 1st Earl of Avon, KG, MC, PC (12 June 1897 – 14 January 1977) was a British Conservative politician, who was Prime Minister from 1955 to 1957. He was also Foreign Secretary for three periods between 1935 and 1955, including during the Second World War. He is best known for his outspoken opposition to appeasement in the 1930s, his diplomatic leadership in the 1940s and 1950s, and the failure of his Middle East policy in 1956 that ended his premiership.

Eden's worldwide reputation as an opponent of appeasement, a "Man of Peace", and a skilled diplomat was overshadowed in the second year of his premiership when the United States refused to support the Anglo-French military response to the Suez Crisis, which critics across party lines regarded as an historic setback for British foreign policy, signalling the end of British predominance in the Middle East. Most historians argue that he made a series of blunders, especially not realizing the depth of opposition to military action by the US. Most historians say that Eden completely dominated the British decision-making process in the Suez crisis. However, Jonathan Pearson argues in Sir Anthony Eden and the Suez Crisis: Reluctant Gamble (2002) that Eden was more reluctant and less bellicose than most historians say.