Lecanora sanctae-helenae is a species of saxicolous (rock-dwelling), crustose lichen in the family Lecanoraceae.

It was formally described as a new species in 1893 by Swiss botanist Johannes Müller Argoviensis, from specimens collected in Saint Helena Island by British amateur naturalist John Charles Melliss.

[1] More than a century later, it was accepted in a 1995 revision of the species complex related to Lecanora subcarnea.

[3] The lichen has a thick, greyish-white to creamish, crust-like thallus lacking soredia and a prothallus.

Lecanora farinacea is morphologically similar, but that species does not contain placodioloic acid.