Sideritis L. (Lamiaceae) includes approximately 150 species of annual and perennial plants distributed mainly in the Mediterranean region. In Turkey, 44 species (55 taxa) are native. Three of these species (5 taxa) are annual and these taxa are included in Burgsdorfia and Hesiodia sections. This study was undertaken to investigate the morphological and anatomical properties of 5 annual taxa of Sideritis. Full descriptions and illustrations of these taxa are given, along with some additional information regarding their ecology and phytogeography. The anatomy of the leaf blade, midrib, and stem of the taxa are described and illustrated.