This is a list of the flora of the South Sandwich Islands, a group of islands in the subantarctic Atlantic Ocean, part of the British overseas territory of South Georgia and the South Sandwich Islands. The list contains flora in the strict sense; that is, plants only. It comprises a single species of vascular plant, 38 mosses, and 11 liverworts. Unusually, not a single species is known to have naturalised on the islands; all are presumed native. The islands also contain 5 species of fungus, 41 lichens and 16 diatoms.