Romuald I (also spelled Romoald and in Italian Romualdo), duke of Benevento (662–687) was the son of Grimoald, king of the Lombards.
The Byzantines were then besieging Benevento and Romuald's valiant defence of the city was failing, when Grimoald showed up and routed the Roman menace.
He received military aid from the possibly Bulgar or Avar Alzeco horde, which had recently entered Italy due to power struggles in Pannonia.
Romuald never saw the kingdom his father had won and so well defended; Perctarit returned and ceased the kingship.
He was succeeded at Benevento by his son by Theodrada, daughter of Duke Lupus of Friuli, Grimoald II.