安斯特岛是苏格兰的岛屿，位于北海，距离西挪威300公里，属于昔德兰群岛的一部分，面积120.68平方公里，最高点海拔高度284米，2001年人口720。

Unst is one of the North Isles of the Shetland Islands, Scotland. It is the northernmost of the inhabited British Isles and is the third largest island in Shetland after the Mainland and Yell. It has an area of 46 square miles (120 km).

Unst is largely grassland, with coastal cliffs. Its main village is Baltasound, formerly the second largest herring fishing port after Lerwick and now the location of a leisure centre and the island's airport. Other settlements include Uyeasound, home to Greenwell's Booth (a Hanseatic warehouse) and Muness Castle (built in 1598 and sacked by pirates in 1627); and Haroldswick, location of a boat museum and a heritage centre.