Rupert Leo Scott Bruce-Mitford (14 June 1914 – 10 March 1994) was a British archaeologist and scholar. He spent the majority of his career at the British Museum, primarily as the keeper of the Department of British and Medieval Antiquities, and was particularly known for his work on the Sutton Hoo ship-burial. Described as the guiding spirit of such research, he oversaw the production of the monumental three-volume work The Sutton Hoo Ship-Burial, termed by the president of the Society of Antiquaries as "one of the great books of the century".

Though Bruce-Mitford was born in London, his preceding two generations had lived largely abroad: his maternal grandparents as early settlers of British Columbia, his paternal grandparents as missionaries in India, and his parents as schoolteachers in Japan. When Bruce-Mitford was five, his father died. His mother was left to raise four sons, of whom Bruce-Mitford was the youngest, on a tiny salary; the stresses were substantial, and he was fostered for a time after his mother had a breakdown. He attended preparatory school with the support of a relative, enrolled at the charity school Christ's Hospital five years later, and, in 1933, earned a Baring Scholarship in History to attend Hertford College, Oxford. Recommending him for a museum curatorship in 1936, the University Appointments Board noted that he "has an exceptional gift for research, a sphere in which he could do work of outstanding merit".

After spending a year as an assistant keeper at the Ashmolean Museum, during which he produced the first standardised chronology of medieval pottery, in December 1937, Bruce-Mitford joined the British Museum's Department of British and Medieval Antiquities. The ship-burial was excavated in 1939, weeks before the outbreak of the Second World War; Bruce-Mitford spent 1940 to 1946 in the Royal Corps of Signals, and returned with responsibility over Sutton Hoo. Bruce-Mitford spent much of the next four decades focused on the subject, publishing dozens of works, studying contemporary graves in Scandinavia (excavating a boat-grave in Sweden and learning Swedish and Danish along the way), and leading a second round of excavations at Sutton Hoo from 1965 to 1970.

In his other duties, Bruce-Mitford excavated at the Mawgan Porth Dark Age Village, published significant works on the Lindisfarne Gospels, the Codex Amiatinus, and (posthumously) Celtic hanging bowls, translated P. V. Glob's book The Bog People into English, and oversaw acquisitions including Courtenay Adrian Ilbert's collection of thousands of clocks and watches, considered the greatest such collection in the world. He also founded the Society for Medieval Archaeology, and served as secretary, and later vice-president, of the Society of Antiquaries. After his retirement from the British Museum in 1977, he served as Slade Professor of Fine Art at the University of Cambridge, a visiting fellow at All Souls College, Oxford, and a faculty visitor in the Department of English at the Australian National University.

Rupert Leo Scott Bruce-Mitford was born on 14 June 1914 at 1 Deerhurst Road, Streatham, London. Following Terence, Vidal and Alaric (Alec), he was the fourth of four sons born to Charles Eustace and Beatrice Jean Bruce-Mitford; a daughter did not survive. Family tradition has it that Rupert's brothers were responsible for his given names, selecting them from their reading: Rupert from Anthony Hope's Rupert of Hentzau, Leo from Rider Haggard's She, and Scott from either Robert Falcon Scott's diary, or his "Message to England".

Bruce-Mitford's paternal great-grandparents, George and Elizabeth Beer, sailed to the Godavari River Delta in India to work as Baptist missionaries in 1836; poor and unordained when they left, they went on, according to Anthony Norris Groves's biographer, to "stand amongst the most tenacious Christian workers of all time". Their two sons, John William and Charles Henry, continued the calling, while their two daughters married schoolteachers in the area. In 1866 John Beer married Margaret Anne Midford, the daughter of an English family living in Machilipatnam. They had five children, including in 1871 Herbert Leonard and in 1875 Eustace, Rupert Bruce-Mitford's father. The family returned to Devon in 1884, when John Beer fell ill. He died shortly after arrival; his wife returned to India, but died there four years later. Eustace Beer, Rupert Bruce-Mitford would later write, was thereby "himself twice orphaned while still a small boy". By 1891 he was in England, having either returned or never left following his father's death. After studying in Exeter he taught English and Classics at Blackburn Grammar School, but then sailed from Genoa in 1901 to teach at the Weihaiwei School in China, an institution for European boys founded by his brother Herbert. He left less than nine months later for Japan, intending to establish his own school there with a curriculum and ethos reflecting his own ideas.

Shortly before his 1902 departure to China, Eustace Beer adopted the surname Bruce-Mitford—perhaps indicative of his desire to separate himself from his family's missionary past. "Mitford" was a take on "Midford", his mother's maiden name, and, perhaps not unintentionally, that of the unrelated Bertram Freeman-Mitford, 1st Baron Redesdale, whose name carried respect in the British expatriate community in Japan. "Bruce" may have been taken from Major Clarence Dalrymple Bruce, an acquaintance who commanded the Weihaiwei Regiment. In Japan Eustace founded the Yokohama Modern School, which targeted the sons of English, and English-speaking, businessmen and missionaries. In 1903, and likely on the basis of his book and articles on Weihaiwei, he was elected a fellow of the Royal Geographical Society; he subsequently became interested in geography and vulcanology, writing additional works on Japan.

Eustace Bruce-Mitford had met Beatrice Allison on his ship to Yokohama, and soon after founding his school recruited her as an assistant teacher; they married on 27 July 1904, at Christ Church, Yokohama. She was the eldest daughter of early settlers of British Columbia, Susan Louisa (née Moir) and John Fall Allison, an explorer, gold prospector, and cattle rancher. In 1908, however, by which time the family had three sons, William Awdry, the Bishop of South Tokyo, announced from the pulpit of Christ Church that "certain marriages of British subjects celebrated in Japan" might not be legally valid, and if so "the couples ... will find that they have been and are living together ... in concubinage and that their children are 'illegitimate'". Though a legal technicality, and one which was remedied by an Act of Parliament in 1912, the announcement disgraced the Bruce-Mitfords, and Eustace lost his leadership of the Yokohama Modern School. He was taken on as an assistant editor by Francis Brinkley, owner and editor of The Japan Mail, though by 1911 had returned to England as a freelance journalist. Rupert Bruce-Mitford was born three years after his family returned from Japan. Three years later, his father left for India to work as an assistant editor at The Madras Mail. Eustace died following a short fever in 1919, when he was forty-four and Rupert five.