The name Radley comes from two Old English words, read and leah, meaning red lea, or red clearing. Excavations, notably at Barrow Hills, have revealed that there has been human use or occupation of the Radley area successively by Neolithic, Bronze Age, Iron Age, Roman, and Saxon people, since before 3000 BC. With the establishment of Abingdon Abbey in 675 AD, Radley, with Bayworth, Sunningwell, Kennington, North and South Hinksey, Dry Sandford, Shippon and the township of Abingdon, all became part of the manor of Barton, owned by the Abbey.

Lower Radley is the oldest part of the modern village, and is composed of houses dating from the fourteenth century to modern times. The main part of Radley now lies to the west of the railway and was mostly developed from the mid-1930s onwards.

Radley Church stands on the site of an earlier Norman building, which is said to have burnt down in about 1290. It was a chapel of the Church of St. Helen in Abingdon for about 600 years. At the end of the Middle Ages Radley Vicarage, part of which is thought to date from the 13th century, is said to have been used by the Abbey as a hunting lodge and the building and its history are the subject of an ongoing investigation by the Radley History Club, in conjunction with the Oxfordshire Buildings Record.

Radley and the other possessions of Abingdon Abbey were surrendered to the Crown on 9th February 1538 upon the dissolution of the monasteries and the manor was granted to Thomas, Lord Seymour of Sudely. When he was executed for treason in 1549, Edward VI gave the manor to his sister Princess (later Queen) Elizabeth, who, in 1569 sold it to George Stonhouse, a Clerk of the Green Cloth. He built his family residence in the park, and was succeeded by his son William, who was created a baronet in 1628 and died in 1631. Sir William's magnificent marble and alabaster monument, sculpted by Nicholas Stone, is on the south side of the sanctuary in Radley Church.

The Stonhouses were ardent loyalists. In 1643, during the Civil War, Radley Church, which was fortified and held by the King's supporters, was attacked by Parliamentarians from Sunningwell. The north aisle and transept were destroyed and have never been replaced. The parish registers record the burial of several officers and troopers who were killed during the skirmish, and the panelled altar tomb in the churchyard is said to be of this date.

In 1727 the Stonhouse residence was replaced by a more compact Georgian building known as Radley Hall, now known as 'The Mansion' of Radley College, and in 1733 Anne Stonhouse was married in Radley Church to Sir William Bowyer, Bart., of Denham Court, Bucks. In 1792 the Rev. Sir James Stonhouse died unmarried and the Radley estate devolved upon his niece, Penelope, Lady Rivers, and then went to a nephew, Sir George Bowyer, 5th Baronet of Denham, who moved to Radley Hall about 1794. In that year he lost a leg at the naval battle of Ushant, and in recognition of his bravery he was made a Vice-Admiral and created 1st Baronet of Radley to go with his Denham baronetcy.

Sir George Bowyer died in 1799 and was succeeded by his son George, who ran into financial difficulties as a result of vain efforts to find coal on his land at Bayworth. In 1815 there was a sale of the contents of Radley Hall and Sir George took his family to live in Italy. He died in 1860, having become a Roman Catholic, and was buried in the family vault in Radley churchyard in the dead of night.

Meanwhile, in 1819, Radley Hall was let to Benjamin Kent, who started a nonconformist school there which lasted until 1844. In 1847 the lease was acquired by the founders of the College of St Peter, now Radley College.

In 1860 a third Sir George Bowyer inherited the Radley Hall estate. He was a Roman Catholic and founded St Edmund's Church in Abingdon. He died in 1883 and the Radley estate of some 1277 acres was sold by auction in July 1889, the main purchaser being Mrs Josephine Dockar-Drysdale of Wick Hall. By prior arrangement, she sold the freehold of Radley Hall and Park to Radley College.

Wick Hall had been built as Wick Farm in the 1720s or 1730s by the Tomkins family, who were maltsters and builders and were responsible for several fine houses in Abingdon, notably Stratton House (1722), the Clock House (1728) and Twickenham House (1756). The property was bought by William Dockar in 1850 and his daughter, the same Josephine Dockar-Drysdale, who had been widowed some years earlier, moved there after his death in 1882. She expanded the house considerably and renamed it Wick Hall.

By the middle of the 19th century Radley had become detached from St Helen's, Abingdon, and was a separate parish with its own vicar, although the advowson, or right of presentation to the benefice, was a bone of contention for nearly 50 years longer, until Radley College purchased it from Miss Bowyer in exchange for Radley Little Wood in 1892.

In 1801 there were 298 people living in Radley, in 34 different houses, with 63 heads of families. Ten years later there were 337 people, living in 42 houses, with 66 heads of families. By 1891 Radley and Kennington combined had 698 people and in the 1901 Census the Radley count was 592. This excluded the masters and pupils of Radley College, and ten years later the figure, including the College, was 927. The 1981 Census recorded 3,562 persons, which was reduced to 2,290 in 1991 largely due to a boundary change at Peachcroft.

The main line of the Great Western Railway was built through Radley in 1844 and the branch line to Abingdon in 1856. At the junction, near Black Bridge, wooden platforms were built for passengers, covered by a timber train shed, and in 1873, when the branch line was extended to Radley, the old Junction Station was lifted bodily and carried to Radley to serve both the main line and the Abingdon branch until a new station was built. The Abingdon Branch was closed to passenger traffic on 8th September 1963 and Radley station buildings were demolished soon afterwards, leaving the station as an unmanned halt.

The village Church of England Primary School adjoins the churchyard and the red brick section was probably built in 1871 after the passing of the 1870 Education Act. The original school house, now a private dwelling, is of an earlier date.

The Bowyer Arms public house alongside the railway was probably built in the mid-1850s and formed part of the Bowyer estate until Morland, the Abingdon brewers, bought the freehold in 1889. It is now owned by Greene King.

At the beginning of the twentieth century there were thirteen farms in Radley, most of them small and self-sufficient, but by the 1970s only two, Peach Croft and Lower Farm, remained. A large area of Lower Radley has been given over for gravel extraction and some of the pits have been filled in with fly ash pumped underground from Didcot Power Station.

There are four established sites for mobile homes in Radley, three of them on the northern edge of the parish and the fourth just over the railway bridge in Lower Radley.

By virtue of the Local Government Act 1972, Radley was transferred from Berkshire to Oxfordshire on 1st April 1974 and lies within the area of the Vale of White Horse District Council.

(This brief history has been compiled, with minor additions, from The History of Radley, published by the Radley History Club in 2002).