Gilli was an eleventh-century Hebridean chieftain whose career coincided with an era of Orcadian overlordship in the Kingdom of the Isles. According to mediaeval saga-tradition, Gilli was a brother-in-law of Sigurðr Hlǫðvisson, Earl of Orkney, having married the latter's sister Hvarflǫð. Traditionally regarded as one of the most powerful Orcadian earls, Sigurðr appears to have extended his authority into the Isles in the late tenth century. Gilli apparently acted as Sigurðr's viceroy or tributary earl in the region. The time frame of Gilli's apparent authority in the Isles is uncertain, and may date as early as the reign of Guðrøðr Haraldsson, King of the Isles, or as late as the period following the death of this man's eventual successor, Rǫgnvaldr Guðrøðarson, King of the Isles. Gilli's