Sir John Port of Etwall, on his death in 1557, left funds to create a grammar school which was then established at the Repton Priory.

[4] Notable alumni, also known as "Old Reptonians", include C. B. Fry, Harold Abrahams,Christopher Isherwood, Jeremy Clarkson, Andy Wilman, Roald Dahl, Adrian Newey and Archbishop Lord Ramsey of Canterbury.

The school was founded by a 1557 legacy in the will of Sir John Port of Etwall, leaving funds for a grammar school at Etwall or Repton, conditional on the students praying daily for the souls of his family:[5] "And I will that the Scollers of the said Scoole everye mornynge at their comynge to the said Scoole, and also at the after nowne at and upon their departinge from the Schole to pray for my parentes soules, my soule..." – The Will of Sir John Port, 6th June 1557Through this private endowment, Repton School was set up as a charity, with early boarding pupils coming from Repton and the neighbouring villages.

Among the first twenty-two names on the register of Repton there are five gentlemen, four husbandmen, nine yeomen, two websters, or weavers, a carpenter and a tanner.

Not long after this, relations between the school and the Thacker family began to deteriorate due to a conflict of interest in accessibility.

[10] In 1865, a commission presided over by Henry Labouchere, 1st Baron Taunton investigated all endowed secondary schools in England, including Repton.

When public schools were attempting to reform, Repton's headmaster at the time lamented the shared tensions from all schools between local boys and boarders, stating that despite a sincere attempt to break down the barriers between them, he had had little success, and a substantial number of applications from "persons of good standing... and good fortune" had been withdrawn when told the boys were "of all classes down to the sons of blacksmiths and washerwomen".

[13] In this decade, the chapel was enlarged, the Science Block, Armoury, Shooting Range and Swimming Bath were built, and the Priory 'Tithe' Barn turned into the Art School.

Gollancz and D. C. Somervell conducted the lessons on “topics of parliamentary reform, the position of women, the future of the Empire, trade unions, individualism and co-operation in industry, the organisation of peace and a League of Nations, conservatism, liberalism, modern Ireland, Alsace-Lorraine and the Russian Revolution.” Repton was considered one of the first schools to offer civics classes in its curriculum.

[18] A war memorial was unveiled on major general Sir John Burnett-Stuart, director of military operations and intelligence, and dedicated by Edwyn Hoskyns, Bishop of Southwell on 1 November 1922.

He took the melody from Hubert Parry's 1888 contralto aria "Long since in Egypt's plenteous land" in his oratorio Judith.

[28] In his 1984 autobiography, Dahl states that when he was a young fag, he was instructed to warm toilet seats for older boys at the school.

The extension was inaugurated in a ceremony led on 10 July 1949, unveiled by lieutenant general Sir Charles Gairdner and dedicated by former Geoffrey Fisher, by then Archbishop of Canterbury.

[35] 1957 saw the 400 year centenary of the school, celebrated with a royal visit from Queen Elizabeth II and Prince Philip, Duke of Edinburgh.

[37] Jeremy Clarkson attended the school, later noting that he had suffered extreme hazing by other students, including being plunged into an ice pool and having his trousers cut in half.

[40] He has stated that this conduct included doing car stunts on the sports pitches, smoking in the chapel, filling all the locks on the premises with Polyfilla, and attending lessons naked from the waist down.

[43] Due to increasing numbers of female pupils in the 1990s, headmaster Graham Jones spearheaded the construction of girls' houses.

In September 2019, the school began using an AI service called AS Tracking in order to monitor students' mental health.

[60] The Olympic gold medalist and world record holder Adam Peaty used Repton's swimming pool as a training facility.

[86] There are scholarships available for drama, sport, art, music, academic capacity and "all-rounder talent"; these do not exceed 20% of the school's fees.

One of this family, Gilbert Thacker, destroyed the church, almost entirely in a day; he did this during the time of Queen Mary, fearing the priory would be recommissioned as part of the Counter-Reformation.

These comprised:[95][96] the footings of areas of the priory remain in some areas, uncovered during construction work in 1922; the bases of a cluster of columns of the former chancel and chapels; fragments of an arch belonging to the former pulpitum, moved to their current position in 1906;[95] fragments of the door surrounds of both the chapter house and warming room.

[99] The overseas schools are owned and funded by local investors, which can be education businesses, real estate corporates, private equity firms or wealthy philanthropists.

[100] RISL remits its profits to Repton School Trust in the UK, which helps fund capital projects and bursaries.

The "Stig" character in Top Gear is said to have been named after the school's pejorative slang term for new boys, a private reference with the producer Andy Wilman, who attended Repton with Clarkson.

[140] In 2014, Southern Derbyshire Magistrates' Court fined the school £10,000 following a guilty plea to a health and safety charge after an incident of negligence.

[141] In April 2019, a teacher tested positive for drink-driving after police saw his vehicle mount a kerb and then enter the school grounds.

[143] In the summer of 2023, a 14-year-old girl died on the school campus at an event organised by Christians in Sport, a third-party religious group.

Criminal barrister of the Queen's Counsel Tim Hannam, Parliamentary Commissioner for Standards Kathryn Stone, and former Chief Constable of Nottinghamshire Susannah Fish (Order of the British Empire, Queen's Police Medal) were identified in press reports as the three governors who quit their roles.

Ms Fish's resignation letter to the chairman of the governors, Mark Shires, said the decision to allow the teacher to remain in post means the school had not taken seriously:"an appalling catalogue [of alleged past misconduct and it was therefore the case that].... safeguarding of pupils past, present and future is now in jeopardy and lacks credibility’.