Masset Inlet is a large saltwater bay located in the heart of the lowland of northern Graham Island, the northernmost and largest island of the Haida Gwaii islands on the North Coast of British Columbia, Canada. It is fed by several rivers, the largest of which is the Yakoun River, and is connected to the open sea of the Dixon Entrance by the narrow Masset Sound and , which opens onto McIntyre Bay. The communities of Port Clements and Sewall are located on the shores of Masset Inlet. The community of Juskatla is located on , the largest of Masset Inlet's arms. There are several islands in the inlet, the largest of which is Kumdis Island, at the inlet's egress to Masset Sound and just north of Port Clements. Masset Inlet helps form the isthmus of the .