The Duchy and later Principality of Benevento is the southernmost Lombard duchy in medieval Italy, centered on Benevento, a city central in the Mezzogiorno.

Being cut off from the rest of Lombard Italy by the papal Duchy of Rome, Benevento is from the first practically independent.

Only during the reigns of Grimoald I of Benevento and the kings from Liutprand on is the duchy closely tied to the kingdom.

After the fall of the kingdom, however, alone of Lombard territories it remains as a rump state, and maintains its de facto independence against all cohallenges for nearly three hundred years, though it is divided after 849.Paul the Deacon refers to Benevento as the "Samnite duchy" after the ancient Italic inhabitants of the area which gave their name to the region Samnium.