Radley was founded in 1847 by William Sewell (1804–79) and Robert Corbet Singleton (1810–81). The first pupil was Samuel Reynolds who in 1897 wrote his reminiscences of the school.
The school was originally housed in Radley Hall, now known as the Mansion, built in the 1720s for the Stonehouse family. Later in the 18th century the estate passed to the Bowyer family, who commissioned Capability Brown to re-design the grounds. After the school was founded, extensive building work took place, beginning with and Chapel, replaced by the current building in 1895, F Social and the Octagon, the earliest living accommodation for the boys, the Clocktower, now the icon of Radley, and the Dining Hall in 1910. Building work has continued throughout the 20th and 21st centuries, with two new Socials, a weights-room/gym, a theatre, and a Real Tennis court being completed since 2006. The grounds include a lake, golf course and woodland.
In 2005 Radley College was one of fifty of the country's leading independent schools which were found guilty by the Office of Fair Trading of running an illegal price-fixing cartel which had allowed them to drive up fees for thousands of parents. Each school was required to pay a nominal penalty of £21,360 and all agreed to make ex-gratia payments totalling three million pounds into a trust designed to benefit pupils who attended the schools during the period in respect of which fee information was shared. Jean Scott, the head of the Independent Schools Council, said that independent schools had always been exempt from anti-cartel rules applied to business, were following a long-established procedure in sharing the information with each other, and that they were unaware of the change to the law (on which they had not been consulted).
The school was inspected by the independent schools Inspectorate in February 2008. The inspection report rated the school's standard of education as "outstanding", which is the highest rating. There was a subsequent inspection by ISI in 2013.
In 2012, the Independent review of A level results, based on government issued statistics, ranked Radley 31st in the UK, ahead of Malvern (32nd), Harrow (34th), Winchester (73rd), Eton (80th) and Wellington (89th)
Rugby is the major sport of the Michaelmas (Autumn) Term. The school fields 21 rugby teams on most Saturdays of the Michaelmas term and some Thursdays. Radley is widely recognised for its rowing reputation, having won events at Henley Royal Regatta on 6 occasions. Only Eton, Shrewsbury and St Edward's have won more events at the Regatta. Some recent Old Radleians have progressed to play cricket for England or captain county level cricket teams. The cricket grounds have been described as 'arguably one of the best in the country' while the sporting facilities have been described as world class.
Sports such as fives, rackets, sailing, badminton and polo are all represented. A real tennis court opened in July 2008, which made Radley College the only school in the world to have fives, squash, badminton, tennis, racquets and real tennis courts all on campus.
Foundation documents include the diary of Robert Corbet Singleton, co-founder and first Warden of Radley has now been published for the first time. It is available on the web. It is a primary resource for the history of educational reform in the mid-19th century and the Oxford Movement.
There have been three official histories of the College, commissioned to celebrate the fiftieth anniversary of the foundation, the centenary and the sesquicentenary respectively.
‘'Sicut Columbae: fifty years of St Peter's College, Radley.’’ By T.D. Raikes and other Old Radleians. James Parker & Co., Oxford and London, 1897. Raikes’ history of the first fifty years of the College is primarily based on reminiscences and first-hand accounts of the earliest years, informed by an author who had been schoolboy, prefect, teacher and close family member of several other Old Radleians. The sections on school sports are particularly valuable.
A second edition was produced by Ernest Bryans in 1925 under an amended title Sicut Columbae: a history of St Peter's College, Radley, 1847–1924. Basil Blackwell, for the Radleian Society, Oxford . Bryans made a few corrections to the earlier text and added chapters which cover the intervening twenty-five years.
The history of Radley College, 1847–1947. By AK Boyd. Basil Blackwell, Oxford, 1948. Boyd's history of Radley was written to celebrate the school's centenary. Like TD Raikes, he had an unrivalled personal knowledge of the school, but he also sought to build on the earlier history with much more documentary material. To this end, he virtually created the school Archives by sourcing all of the extant material from anyone who had any past connection with the school, occasionally commissioning transcripts where the original was retained by the families who owned it. The strength of Raikes' history was the depth of first-hand memoirs; Boyd's in his use of, and extensive quotations from, the source material.
No ordinary place: Radley College and the public school system. By Christopher Hibbert. John Murray, London, 1997. ISBN 0-7195-5176-5. Christopher Hibbert's history of the College was commissioned to celebrate the 150th anniversary of its foundation in 1997. Hibbert, himself a former Radleian, was described as 'the leading popular historian now living in England.' His approach was to place the school's history within the context of public school education in the 19th and 20th centuries. This allows a thematic approach within each chronological section.
Recollections: the life and travels of a Victorian architect. Sir Thomas Graham Jackson, 1835–1924. Ed. by Nicholas Jackson. With an introduction and gazetteer by James Bettley. Unicorn Press, London, 2003. ISBN 0-906290-72-4. Thomas Graham Jackson was the architect who designed the infirmary and cloisters, chapel, dining hall, H Social, the South African War memorial, and the War Memorial gateway (Mem Arch). Updated version of the 1950 edition edited by Basil Jackson
Looking at Radley: an architectural and historical survey of the earlier buildings. By M.T. Cherniavsky & A.E. Money. Radley College,  Based on three articles and a course on the history of the buildings taught by Michael Cherniavsky whilst on a sabbatical at Radley College in 1979. He describes the exterior views of Radley that would still be recognised by a visitor from the time of Warden Sewell in the 1850s. Tony Money, Archivist at Radley, then wrote about the various interior uses to which the buildings have been put over the years. The book is illustrated from photos in the College Archives.
Radley Hall: the rediscovery of a country house. By Alison Maguire in Architectural History, Vol. 44, Essays in Architectural History Presented to John Newman (2001). Detailed study of the Mansion by a member of the architectural team responsible for its renovation after the fire in 1997
Capability Brown and the eighteenth-century English landscape. 2nd edn. By Roger Turner. Chichester, Phillimore, 1999. ISBN 1-86077-114-9 A brief note in the gazetteer about Brown's work for Sir William Stonhouse at Radley Hall in 1770–1.
The fauna and flora of Radley and the neighbourhood. By the Radley College Natural History Society. James Parker, Oxford, 1906. Pioneering survey compiled from the field notes of the College Natural History Society, organised by classes and genera with locations
The Radley district: its history, botany, entomology and geology. Ed. by T Field. Parker & Son, Oxford, 1912. Individual chapters on history, botany and entomology by the Warden and staff of Radley College, and on geology by M Odling, F.G.S., formerly a boy at the school, who became one of the first Demonstrators in Geology at the University of Leeds. Material was drawn from the College Natural History Society records and excursions
Manly and muscular diversions: public schools and the nineteenth-century sporting revival. Tony Money. Duckworth, London, 1997. ISBN 0-7156-2793-7. Argues that the political and economic stability of the British upper class and, more importantly, the enthusiasm of boys at English boarding schools, was a crucial factor in the spread of contemporary team sports around the world. Draws extensively on material from Radley College Archives.
Football at Radley, 1847–2000. Tony Money. [Radley College, 2000] Study of the development of football in the 19th century as individual schools created their own game, including Radley Football, and the subsequent adoption of Rugby Football as a nationally recognised sport.
The College Archives contain a collection of unpublished memorabilia by Old Radleians. The most significant biographies about specific Wardens and staff are:
A forgotten genius: Sewell of St. Columba's and Radley. By Lionel James. Faber and Faber, London, 1945. Biography of William Sewell, founder of Radley College, by a former member of staff. Makes extensive use of Sewell's diaries, letters and sermons
A memoir of the Reverend George Wharton, Precentor of Saint Peter's College Radley. By Roscoe Beddoes. Oxford University Press, 1931. ‘Kitty’ Wharton was the most eccentric and long-serving of the 19th century schoolmasters of Radley
Thomas Field, D.D.: a memoir. By Harold S. Goodrich. SPCK, London, 1937. Thomas Field was Warden of Radley, 1897–1913.
In addition, biographies and autobiographies by Old Radleians often contain brief accounts of time at the school.
The school lent its name to the thirty-first steam locomotive (Engine 930) in the Southern Railway's Class V of which there were 40. This Class was also known as the Schools Class because all 40 of the class were named after prominent English Public Schools. 'Radley', as it was called, was built in 1934 and was withdrawn in 1962. A nameplate from 930, Radley, is now displayed in the stationery department of Shop (the College's shop)
Radley village has a local history society who have produced a number of publications and maintain an archive of local material.
Radley vicarage by Radley History Club, 2005. A report of a 'buildings record' survey and archive research undertaken to determine the history, construction, and later development of this 14th-century building
The history of Radley by Patrick Drysdale … [and others] Radley History Club, 2002. History of the village from prehistory to the presentR C Singleton (1847–1851)
W B Heathcote (1851–1852)
W M Sewell (1853–1861)
R W Norman (1861–1866)
W Wood (1866–1870)
C Martin (1871–1879)
R J Wilson (1880–1888)
Henry Lewis Thompson, (1888–1896)
T Field (1897–1913)
Gordon Selwyn (1913–1919)
Adam Fox (1919–1925)
W H Ferguson (1925–1937)
J C Vaughan Wilkes (1937–1954)
W M M Milligan (1954–1968)
D R W Silk (1968–1991)
Richard Morgan (1991–2000)
Angus McPhail (2000–2014)
John Moule (2014–)
Boyd Alexander, the African traveller and ornithologist.
James Bachman, comic writer and actor.
Harry Bicket, conductor.
C. E. Bowden, WW1 pilot and pioneer of IC engined model flight and radio control.
Gerald Brenan, writer.
William Burdett-Coutts, producer Assembly Festival
James Burton, conductor and composer.
Richard Toby Coke, UKIP politician.
Collingwood Tinling, builder of first jet engine
Peter Cook, comedian.
Jamie Dalrymple, cricketer. Has represented England in a number of ODIs.
Ted Dexter, cricketer.
Alexander Downer, former Australian Foreign Minister.
Mark Durden-Smith, television presenter.
Marc Edwards, sports correspondent with BBC World News (formerly with CCTV International, France 24 and Eurosport).
Ivan Ewart, British naval officer and charity worker.
Jeremy Flint, bridge player.
George Freeman, Conservative Member of Parliament for Mid Norfolk.
Andrew Gant, chorister and composer.
Richard Gibson, actor, best known as Herr Flick in the BBC series 'Allo 'Allo!.
Nicholas Hannen actor
Robert Hall, BBC Special Correspondent.
Simon Hart, Conservative Member of Parliament for Carmarthen West and South Pembrokeshire
Christopher Hibbert, historian.
Sir Robert Hodgson, Air Chief Marshall
Cyril Holland, son of Oscar Wilde.
George Hollingbery, Conservative Member of Parliament for Thirsk and Malton
Charles Howard, 20th Earl of Suffolk, pioneering bomb disposal expert in WW2.
Alan Huggins, Hong Kong judge
Ben Hutton, cricketer.
Jamie Laing, Reality TV star of Made in Chelsea.
Air Vice-Marshal Thomas Langford-Sainsbury CB OBE DFC AFC.
Desmond Llewelyn, actor best known for playing Q in many James Bond films.
James Lovegrove, SF novelist.
Sir Edgar Ludlow-Hewitt, Air Chief Marshall
James Charles Macnab of Macnab, soldier and chief of Clan Macnab.
Sir George Mallaby, public servant, High Commissioner to New Zealand.
J.N.S.H Master CBE
Sir Charlie Mayfield MBA, OBE, CEO of Waitrose and John Lewis Partnership
J.X. Merriman, South African statesman.
Harold Monro, founder of the Poetry Bookshop.
Andrew Motion, poet and former Poet Laureate.
Andrew Nairne, director of Kettle's Yard.
Sandy Nairne, director of the National Portrait Gallery.
James Pearce, journalist and presenter for BBC Sport.
Edgar Prestage, historian and Portuguese scholar.
Dennis Price, actor.
Michael Reeves, film director.
S.H. Reynolds, clergyman.
Professor Sir Mike Richards, UK National Cancer Director.
Lord Scarman, judge.
Brough Scott, horse racing journalist, radio and television presenter, and former jockey.
Tom Shakespeare, sociologist and broadcaster.
Clive Stafford Smith, campaigning lawyer.
Andrew Strauss, cricketer (Former England captain. Captained England to an Ashes victory in the summer of 2009. Represented Middlesex. Opening Batsman.)
Jeremy Stuart-Smith, High Court judge.
Sir Reginald Stubbs, colonial governor.
Lieutenant-Colonel Rupert Thorneloe MBE, killed in action in Afghanistan on 1 July 2009
Nigel Twiston-Davies, Cheltenham Gold Cup winning horse trainer.
Peter Wildeblood, journalist and playwright and celebrated gay rights campaigner.
Richard Wilson, Baron Wilson of Dinton, former UK Cabinet Secretary.
Major General Sir Edward Woodgate, KCMG, CB, who died of wounds sustained during the Battle of Spion Kop.
Charles Worsley, cricketer who played first-class cricket for Northamptonshire.
Ivor Vincent, MBE, CMG, British diplomat