TheElymus semicostatusgroup is revised taxonomically. Previously, 32 taxa have been described in the group. Here, nine of these are accepted as species and two as interspecific hybrids, namely,E. semicostatus, E. macrochaetus, E. validus, E. abolinii, E. fedtschenkoi, E. nevskii. E. praeruptus, E. panormitanus, E. nepalensis, E. ×brachyphyllus, andE. ×macrolepis. Synonymy, morphological descriptions, illustrations, chromosome numbers, and a key to the taxa are provide