We investigated the morphology of the Silene gigantea complex across its distribution range in the Balkan Peninsula, south-western Turkey and Cyprus. We performed a factorial analysis for mixed quantitative and qualitative variables followed by k-means analyses to determine the most probable morphological clustering within the species. A linear discriminant analysis was then computed using the DISQUAL method to test the a priori classification. The results indicate that three entities, which are consistent with the previously published taxonomic treatment, can be recognised. Moreover, our results show that the distribution of S. gigantea subsp. hellenica can be extended to Turkey, and that S. gigantea subsp. rhodopea is actually absent from this country, in contradiction to previous assessments. The global distribution of the S. gigantea complex is established and the morphological characteristics of each subspecies are discussed.