Barnard Castle School is a co-educational private day and boarding school in the market town of Barnard Castle, County Durham, in the North East of England. It is a member of The Headmasters' and Headmistresses' Conference (HMC). It was founded in 1883 with funding from a 13th-century endowment of John I de Balliol and the bequest of the local industrialist Benjamin Flounders. The ambition was to create a school of the quality of the ancient public schools at a more reasonable cost, whilst accepting pupils regardless of their faith.

Barnard Castle is a market town on the north bank of the River Tees, in County Durham, England. The town is named after and built around a medieval castle ruin. The town's Bowes Museum's has an 18th-century Silver Swan automaton exhibit and paintings by Goya and El Greco.