Tasso (or Taso) (died 617) was the joint Duke of Friuli with his younger brother Kakko from their father's death (611) to their own. Their father was Gisulf II and their mother Romilda of Friuli. In or around 611, Gisulf was killed fending off an Avar invasion.
Tasso, along with his brothers Kakko, Radoald, and Grimoald, escaped the Avars and evaded capture, successfully setting themselves up as Gisulf's successors. During their reign, they ruled over the Slavs of the valley of the Gail up to Matrei and imposed a tribute upon them.