Pandulf III (died 1060) was the prince of Benevento in the Mezzogiorno in medieval Italy, first as co-ruler with his father, Landulf V, and grandfather, Pandulf II, from 1012 or thereabouts to 1014, when the elder Pandulf died. He co-ruled with his father until his death in 1033. Thereafter he was the primary ruler until his abdication in 1059 (except for a brief period).
Immediately after the death of Pandulf II, the citizens of Benevento led a revolt against the two princes, father and son. The rebellion failed to dislodge the princes from power. However, the citizens did force concessions of authority to themselves and the city's aristocracy. The Annales say facta est communitas prima: "the first commune is made."
Benevento was forced to make submission to the Byzantine Empire, whose Italian catepan Boiannes had built the fortified city of Troia nearby. In 1022, the Emperor Henry II joined his army with two other armies under Poppo of Aquileia and Pilgrim of Cologne at Benevento, which submitted after a quick siege. From there they marched on Troia, but failed to take it. After making submission to the Western Emperor, Landulf is not heard of again in the pages of history until his death and his son takes his place.
In August or September 1038, Pandulf associated his own son, Landulf VI, in the principality. Such co-regency was a tradition dating back to the will of Atenulf I of Capua in 910. In 1041, it was his brother Atenulf who incited a rebellion because he was not included in the regency. To the author of the meagre Annales Beneventani, this fuit [...] coniuratio secundo, the second conspiracy to remove the princes. Like the first of 1014, it failed.