Tustna is an island in Aure Municipality in Møre og Romsdal county, Norway. The 89-square-kilometre (34 sq mi) island lies in the western part of the municipality. The island of Tustna lies west of the islands of Stabblandet and Solskjelsøya; to the northeast of the islands of Frei and Nordlandet; and south of the island of Smøla. The Edøyfjorden runs along the northern shores of the island, the Vinjefjorden (and Halsafjorden) are to the south, the Freifjorden is to the southwest, the Talgsjøen is to the west, and the open Norwegian Sea is to the northwest.
The island of Tustna and surrounding islands was part of the municipality of Tustna from 1 January 1874 until 1 January 2006 when it was merged into Aure Municipality. The main population centers on the island are Tømmervåg on the western coast, Leira on the northern coast, and Gullstein on the eastern coast. The island is connected to neighboring Stabblandet in the east by a bridge at the village of Tustna, and there is a ferry connection from Tømmervåg to the town of Kristiansund. There is another ferry connection from the northern coast of Tustna to the island of Edøya in Smøla Municipality.
Tustna is a former municipality in Møre og Romsdal county, Norway. The administrative centre was the village of Gullstein. The municipality is located in the present-day Aure Municipality. The municipality included the main islands of Tustna, Stabblandet, and Solskjelsøya, as well as many smaller, surrounding islets between the Edøyfjorden and the Vinjefjorden. In 2006, when the municipality was merged into Aure, it was 141 square kilometres (54 sq mi).
Tustna was originally a part of the municipality of Edøy (see formannskapsdistrikt). A meeting held on 17 March 1863 decided to build a church on Tustern (which was the name of the island at that time) and thereby gain status as a separate parish. Gullstein Church was built in the village of Gullstein on the eastern side of the island in 1864. A royal resolution of 3 May 1873 directed that Tustern be separated from Edøy to create a separate municipality. This happened on 1 January 1874. The new municipality had an initial population of 1,179. On 1 January 1965, the part of Tustna on the island of Ertvågsøy (population: 85) was transferred to neighboring Aure Municipality to the east. On 1 January 2006, all of Tustna Municipality was merged into Aure Municipality. At its end, Tustna had a population of 1,006.