© TÜBİTAK.Marrubium zeydanlii (Lamiaceae) is described as a new species from Turkey. It is similar to M. depauperatum and M. sivasense; however, it is distinguished from M. depauperatum by having lanate hairs on the stem, oblanceolate dentate leaves, 4–6-flowered verticillasters. It is also distinguished from M. sivasense by having lanate hairs on the stem, oblanceolate leaves, and shorter petals. The pollen grains are radially symmetrical and isopolar, the shape is oblate-spheroidal with the polar axes 16.7–20 µm and the equatorial axes 17.6–19.3 µm. trnL-F region was used to identify the phylogenetic position of the newly described species. The results of the current study indicated that the new species show significant morphological and molecular differences from closely related species. Taxonomic descriptions and micromorphology of pollen are examined and also, some notes on the ecology, phytogeographic, conservation status, and distribution map of the new species are presented.