Oundle School is a public school (English fee-charging boarding and day school) for pupils 11–18 situated in the market town of Oundle in Northamptonshire, England. The school has been governed by the Worshipful Company of Grocers of the City of London since its foundation by Sir William Laxton in 1556. The school's alumni – known as Old Oundelians – include entrepreneurs, scientists, politicians, military figures and sportspeople.
Oundle has eight boys' houses, five girls' houses, two day houses, a junior house and a junior day house. Together these accommodate more than 1100 pupils, generally between the ages of 11 and 18. It is the third-largest boarding school in England after Eton and Millfield.