Arechis II (also Aretchis, Arichis, Arechi or Aregis) (died August 26, 787) is Duke (and later Prince) of Benevento, in southern Italy, from 758 until his death.
While he seeks to expand Benevento's influence into areas of Italy still controlled by the Byzantine Empire, he also has to resist attacks by Charlemagne, who is building a Frankish empire and has conquered northern Italy.