Dorothee Island (French: Ile Dorothee) is an island in South Australia which is part of the Pearson Isles which itself is part of the larger island grouping known as the Investigator Group. It is located about 69 kilometres (43 mi) west south-west of Cape Finniss on the west coast of Eyre Peninsula. It was discovered as part of the Pearson Isles by Matthew Flinders on 13 February 1802.