The Stjørnfjord or Stjørnfjorden is an arm of Trondheimsfjord that flows through the municipalities of Bjugn, Ørland, and Rissa in Sør-Trøndelag county, Norway. The long fjord stretches southwest from the mouth of the Nordelva river near the village of Råkvåg to the Trondheimsfjord near Brekstad and Austrått. The inner part of the fjord splits into two smaller arms, the Nordfjord and Sørfjord. The Bjugnfjorden lies about north of the fjord.