The genus Miscanthus in South Korea is revised based on herbarium studies and field observations. Three species, two varieties, five forms and one hybrid are recognized and a new combination is proposed: i.e., Miscanthus sinensis Andersson var. sinensis (further divided into four forms: f. sinensis, f. variegatus (Beal) Nakai, f. purpurascens (Andersson) Nakai and f. gracillimus (Hitchc.) Ohwi; M. sinensis var. condensatus (Hack.) Makino; M. sacchariflorus (Maxim.) Benth. & Hook. f. ex Franch. var. sacchariflorus (further divided into two forms: f. sacchariflorus and f. latifolius Adati); M. sacchariflorus var. gracilis Y. N. Lee, M. ×longiberbis (Hack.) Nakai f. longiberbis; M. ×longiberbis (Hack.) Nakai f. ogiformis (Honda) Ibaragi, comb. et stat. nov. and M. latissimus Y. N. Lee. A key to the taxa and morphological descriptions for each taxon are presented. Lectotypes of Miscanthus ionandros Nakai, M. sinensis f. transiticus Nakai, M. chejuensis Y. N. Lee and M. kokusanensis Nakai & Honda as well as Neotypes of M. sacchariflorus f. latifolius Adati and M. latissimus Y. N. Lee are designated here.