Ocellularia gueidaniana is a species of corticolous (bark-dwelling) lichen in the family Graphidaceae. Found in Singapore, it was formally described as a new species in 2015 by Gothamie Weerakoon and Robert Lücking. The type specimen was collected by the first author at a low elevation in the Bukit Timah Nature Reserve. It is only known to occur at the type locality. The species epithet honours lichenologist Cécile Gueidan.