Stonor is a village about 4 miles (6.4 km) north of Henley-on-Thames in South Oxfordshire. It is in the Stonor valley in the Chiltern Hills about 300 feet (91 m) above sea level.

For most of its history Stonor was called Upper Assendon and was a hamlet in an exclave of Pyrton parish. In 1896 the detached part was made into a new civil parish of Stonor, named after the adjacent country house at Stonor Park. In 1922 Stonor and Pishill civil parishes were merged. During and after the English Reformation the Stonor family and many other local gentry were recusants. In 1581 the Jesuit priests Edmund Campion and Robert Parsons lived and worked at Stonor Park, and on 4 August 1581 a raid on the house found a press on which Roman Catholic publications had secretly been printed. The elderly Lady Cecily Stonor, her son John, the Jesuit priest William Hartley, the printers and four servants were taken prisoner, and in 1585 Hartley was exiled. Despite continued prosecutions and fines the Stonors and a number of Upper Assendon families remained Roman Catholic throughout the 17th and 18th centuries, attending Mass at the Stonors' 12th century private chapel. Between 1716 and 1756 John Talbot Stonor, Vicar Apostolic of the Midland District used Stonor Park as his headquarters. In the first half 19th century the number of Roman Catholics in Upper Assendon increased, partly by local people converting, possibly aided by the fact that the only local school at the time was a Roman Catholic one endowed by the Stonors. The 1851 census recorded 50 Catholics in the village, but in the final quarter of the 19th century the numbers sharply declined.

Stonor Cricket Club was founded in 1797. It has occupied its current ground next to Stonor Park for more than a century.