Field Marshal Edmund Henry Hynman Allenby, 1st Viscount Allenby, GCB, GCMG, GCVO (23 April 1861 – 14 May 1936) was a senior British Army officer and imperial governor. He fought in the Second Boer War and in the First World War, in which he led the British Empire's Egyptian Expeditionary Force (EEF) during the Sinai and Palestine Campaign against the Ottoman Empire in the conquest of Palestine.

The British succeeded in capturing Beersheba, Jaffa, and Jerusalem from October to December 1917. His forces occupied the Jordan Valley during the summer of 1918, then went on to capture northern Palestine and defeat the Ottoman Yildirim Army Group's Eighth Army at the Battle of Megiddo, forcing the Fourth and Seventh Army to retreat towards Damascus. Subsequently, the EEF Pursuit by Desert Mounted Corps captured Damascus and advanced into northern Syria.

During this pursuit, he commanded T. E. Lawrence ("Lawrence of Arabia"), whose campaign with Faisal's Arab Sherifial Forces assisted the EEF's capture of Ottoman territory and fought the Battle of Aleppo, five days before the Armistice of Mudros ended the campaign on 30 October 1918. He continued to serve in the region as High Commissioner in Egypt from 1919 until 1925, a position that meant he effectively ruled Egypt during this period.

Allenby was born on 23 April 1861, the son of Hynman Allenby and Catherine Anne Allenby (née Cane) and was educated at Haileybury College. His father owned 2,000 acres (810 ha) in Norfolk and Felixstowe House, at Felixstowe, then a fishing village. This was a summer home until the family settled there permanently after Hynman Allenby's death in 1878.

Allenby had no great desire to be a soldier, and tried to enter the Indian Civil Service but failed the entry exam. He sat the exam for the Royal Military College, Sandhurst in 1880 and was commissioned as a subaltern, with the rank of lieutenant, in the 6th (Inniskilling) Dragoons on 10 May 1882. He joined his regiment in South Africa later that year, taking part in the Bechuanaland Expedition of 1884–85. After serving at the cavalry depot in Canterbury, he was promoted to captain on 10 January 1888 and then returned to South Africa.

Allenby returned to Britain in 1890 and he sat – and failed – the entry exam for the Staff College at Camberley. Not deterred, he sat the exam again the next year and passed. Captain Douglas Haig of the 7th Hussars also entered the college at the same time, thus beginning a rivalry between the two that ran until the First World War. Allenby was more popular with fellow officers, even being made Master of the Draghounds in preference to Haig who was the better rider; Allenby had already developed a passion for polo. Their contemporary James Edward Edmonds later claimed that the staff at the Staff College thought Allenby dull and stupid but were impressed by a speech that he gave to the Farmers' Dinner, which had in fact been written for him by Edmonds and another.

He was promoted to major on 19 May 1897 and was posted to the 3rd Cavalry Brigade, then serving in Ireland, as the brigade major in March 1898.

Following the outbreak of the Second Boer War in October 1899, Allenby returned to his regiment, and the Inniskillings embarked at Queenstown and landed at Cape Town, Cape Colony, later that year. He took part in the actions at Colesberg on 11 January 1900, Klip Drift on 15 February 1900 and Dronfield Ridge on 16 February 1900, and was mentioned in dispatches by the commander-in-chief, Lord Roberts on 31 March 1900.