Field Marshal Horatio Herbert Kitchener, 1st Earl Kitchener (/ˈkɪtʃɪnər/; 24 June 1850 – 5 June 1916) was an Anglo-Irish British Army officer and colonial administrator. Kitchener came to prominence for his imperial campaigns, his involvement in the Second Boer War, and his central role in the early part of the First World War.

Kitchener was credited in 1898 for having won the Battle of Omdurman and securing control of the Sudan, for which he was made Baron Kitchener of Khartoum. As Chief of Staff (1900–1902) in the Second Boer War he played a key role in Lord Roberts' conquest of the Boer Republics, then succeeded Roberts as commander-in-chief – by which time Boer forces had taken to guerrilla fighting and British forces imprisoned Boer and African civilians in concentration camps. His term as commander-in-chief (1902–1909) of the Army in India saw him quarrel with another eminent proconsul, the viceroy Lord Curzon, who eventually resigned. Kitchener then returned to Egypt as British agent and consul-general (de facto administrator).

In 1914, at the start of the First World War, Kitchener became secretary of state for war, a cabinet minister. One of the few to foresee a long war, lasting for at least three years, and having the authority to act effectively on that perception, he organised the largest volunteer army that Britain had seen, and oversaw a significant expansion of material production to fight on the Western Front. Despite having warned of the difficulty of provisioning for a long war, he was blamed for the shortage of shells in the spring of 1915 – one of the events leading to the formation of a coalition government – and stripped of his control over munitions and strategy.

On 5 June 1916, Kitchener was making his way to Russia on HMS Hampshire to attend negotiations with Tsar Nicholas II when in bad weather the ship struck a German mine 1.5 miles (2.4 km) west of Orkney, Scotland, and sank. Kitchener was among 737 who died.

Kitchener was born at Gunsborough Villa, north of Listowel, County Kerry, in Ireland, son of army officer Henry Horatio Kitchener (1805–1894) and Frances Anne Chevallier (1826–1864); daughter of John Chevallier, a clergyman, of Aspall Hall, and his third wife, Elizabeth (née Cole).

Both sides of Kitchener's family were from Suffolk, and could trace their descent to the reign of William III; his mother's family was of French Huguenot descent. His father had only recently sold his commission and bought land in Ireland, under the Incumbered Estates (Ireland) Act 1849 designed to encourage investment into Ireland after the Irish Famine. In later life Kitchener only once revisited his childhood home, in the summer of 1910 at the invitation of Henry Petty-Fitzmaurice, 5th Marquess of Lansdowne; he astonished the estate's owners by recalling the Irish names of many of the fields. Although sometimes labeled by military historians as Irish or Anglo-Irish (a group which provided a disproportionate number of senior British officers – see Irish military diaspora), Kitchener did not regard himself as such and was known to quote the saying misattributed to the Duke of Wellington that "a man may be born in a stable, but that does not make him a horse".

In 1864 the family moved to Switzerland, where the young Kitchener was educated at Montreux, then at the Royal Military Academy, Woolwich. Pro-French and eager to see action, he joined a French field ambulance unit in the Franco-Prussian War. His father took him back to Britain after he caught pneumonia while ascending in a balloon to see the French Army of the Loire in action.

Commissioned into the Royal Engineers on 4 January 1871, Kitchener was reprimanded by the Duke of Cambridge, the commander-in-chief, as his service in France had violated British neutrality. He served in Palestine, Egypt and Cyprus as a surveyor, learned Arabic, and prepared detailed topographical maps of the areas. His brother, Lt. Gen. Sir Walter Kitchener, had also entered the army and was Governor of Bermuda from 1908 to 1912.