Koyamasia is a genus of flowering plants in the family Asteraceae. It includes two species of perennials native to Peninsular Malaysia and Thailand.Koyamasia calcarea (Kitam.) H.Rob. – northern Thailand Koyamasia curtisii (Craib & Hutch.) Bunwong, Chantar. & S.C.Keeley – Thailand and Peninsular Malaysia (Langkawi)