A new species of terrestrial crab, Geosesarma notophorum (Grapsidae, Sesarminae), is described from Pulau Lingga, an island east of Sumatra, Indonesia. Geosesarma notophorum belongs to the G. malayanum group of species, but can be distinguished from congeners in having iridescent green eyes, the shape of its carapace, form of its external orbital tooth, and structure of the male first pleopod. The female is unusual in carrying the young crabs on its back.