Barther Oie is an uninhabited island in the German federal state of Mecklenburg-Vorpommern and lies in the lagoon of Barther Bodden, between the town of Barth and the Baltic seaside resort of Zingst.

The Baltic Sea island has an area of about 850 by 800 metres (2,790 ft × 2,620 ft) and rises, like its sister island of Kirr, only 1 metre (3 ft 3 in) above sea level.

Today the island is a nature reserve in the West Pomeranian Lagoon Area National Park.