The Duchy of Benevento was the southernmost Lombard duchy in the Italian Peninsula that was centered in Benevento, a city in Southern Italy. Lombard dukes ruled Benevento from 571 to 774, when the Kingdom of the Lombards was conquered by the Kingdom of the Franks. Being cut off from the rest of the Lombard possessions by the papal Duchy of Rome, Benevento always had held some degree of independence. Only during the reigns of Grimoald (r. 662–671) and the kings from Liutprand (r. 712–744) on was the duchy closely tied to the Kingdom of the Lombards. After the fall of the kingdom in 774, the duchy became the sole Lombard territory which continued to exist as a rump state, maintaining its de facto independence for nearly 300 years as the Principality of Benevento.
Paul the Deacon referred to Benevento as the "Samnite Duchy" (Ducatum Samnitium) after the region of Samnium.