The genus Grisollea includes three species found in the West Indian Ocean basin. Grisollea myriantha occurs in the Comoro Islands and Madagascar, while Grisollea thomassetii is restricted to the Seychelles. A new species, Grisollea crassifolia, is described from eastern Madagascar. This revision provides a key to the species, descriptions, illustrations, maps, conservation status assessments, and an overview of the placement of the genus within Stemonuraceae.