The feudal barony of Plympton was a large feudal barony in the county of Devon, England, whose caput was Plympton Castle and manor, Plympton. It was one of eight feudal baronies in Devonshire which existed during the medieval era. It included the so-called Honour of Christchurch in Hampshire, which was not however technically a barony. The de Redvers family, first holders of the barony, were also Lords of the Isle of Wight, which lordship was not inherited by the Courtenays, as was the barony of Plympton, as it had been sold to the king by the last in the line Isabel de Redvers, 8th Countess of Devon (1237–1293).

Plympton is a suburb of the city of Plymouth in Devon, England. It is in origin an ancient stannary town. It was an important trading centre for locally mined tin, and a seaport before the River Plym silted up and trade moved down river to Plymouth and was the seat of Plympton Priory the most significant local landholder for many centuries.