Cornitibia is a monotypic genus of spiders in the family Linyphiidae containing the single species, Cornitibia simplicithorax. It is endemic to Nepal, where it was found in Alnus forest along a river in Ilam District.
The male has a body length of 1.93 mm. The female is unknown.
The genus is named after the tusklike male palpal tibia apophysis, from Latin "cornus" ("horn"). The species name refers to the unmodified shape of the male carapace.