The paper presents a taxonomic and nomenclatural account on four taxa of Thymus published by Ukrainian monographers of the genus M.V. Klokov (1896–1981) and N.O. Desjatova-Shostenko (1889–1968), namely Th. dimorphus [unranked] steppaceus, Th. eltonicus, Th. kirgisorum var. creticola, and Th. pulegioides subsp. ucrainicus. Based on the original material examination, a lectotype from herbarium CWU is designated for each name. Several taxonomic changes are proposed, including the treatment of Th. dimorphus [unranked] steppaceus as a taxonomic synonym of Th. dimorphus, Th. eltonicus as synonym of Th. kirgisorum, and Th. pulegioides subsp. ucrainicus as synonym of Th. pulegioides var. pulegioides. The name Th. kirgisorum var. creticola is proposed as the accepted name for this variety.