Northmavine (meaning ‘the land north of the Mavis Grind’) is a peninsula of Shetland in Scotland. It is in the north west of the island, and contains the villages of Hillswick, Ollaberry, and North Roe. The peninsula includes the northernmost part of Mainland, and the civil parish, spelt Northmaven, comprises a number of adjacent islands, and measures by .
An isthmus, Mavis Grind, about a hundred yards across, forms the sole connection with the rest of Mainland.
The coast is indented by numerous bays and consists largely of high, steep rocks. It has a number of high, fissured, cavernous cliffs on the west coast and consists of many skerries, islets, and offshore rocks.
The interior has a very small amount of arable land; it consists mostly of rough, rising ground, including Ronas Hill, the highest point in all Shetland.
Remains of ancient watch houses and remains of barrows and forts are numerous.