A morphometric study on five populations of the Onosma echioides complex was carried out through univariate analysis, principal coordinate analysis and cluster analysis (the unweighted pair-group method with arithmetic mean; UPGMA). In consideration of the quantitative morphological variability, of the known karyological homogeneity and of the allopatric distribution of the taxa, we propose here to treat this complex as a single species subdivided in four subspecies. The names O. angustifolia Lehm., O. canescens J. et C. Presl, O. dalmatica Scheele, O. echioides var. columnae Lacaita, O. echioides var. veronensis Lacaita and O. javorkae Simonkai are typified. The new combinations O. echioides subsp. angustifolia (Lehm.) Peruzzi & N. G. Passal., O. echioides subsp. canescens (J. et C. Presl) Peruzzi & N. G. Passal. and O. echioides subsp. dalmatica (Scheele) Peruzzi & N. G. Passal. are proposed. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157, 763–774.