A comprehensive taxonomic revision of Stipa subsects. Stipa and Tirsae is presented. We analyzed the pattern of morphological variation of the taxa included in both subsections through the study of 1353 vouchers from 27 herbaria. Variation in floral and leaf morphology was further explored to revaluate taxon limits in 165 specimens using univariate analyses (Anova, Tukey test and, χ² test), and multivariate tests (principal components analysis and discriminant analysis). We found that one species of subsect. Tirsae plus three species and five subspecies of subsect. Stipa can be distinguished based on morphological characters. For each taxon, we present a dichotomous key, a list of synonyms, detailed morphometric descriptions, illustrations, and distribution maps. In addition, neotypes are proposed for S. pulcherrima var. mollis (subsection Stipa) and S. aperta (subsection Stipa), and a lectotype is proposed for S. cerariorum (subsection Tirsae). Likewise, two new combinations are proposed: Stipa subsection Tirsae (Martinovský) R. Gonzalo, and Stipa turkestanica subspecies macroglossa (P.A Smirn.) R. Gonzalo.