A taxonomic revision of the populations belonging to the Dianthus sylvestris Wulfen group (Caryophyllaceae) occurring in central and southern Italy, Sardinia and Sicily has been made. This group is represented in the surveyed territories by 17 morphologically and ecologically well differentiated species: Dianthus arrosti C. Presl, D. siculus C. Presl, D. graminifolius C. Presl, D. cyathophorus Moris, D. gasparrinii Guss., D. longicaulis Ten., D. virgatus Pasquale, D. tarentinus Lacaita, D. morisianus Vals., D. japygicus Bianco & Brullo, D. sardous Bacch., Brullo, Casti & Giusso, D. busambrae Soldano & F. Conti, D. brachycalyx Huet sp. nov., D. oliastrae sp. nov., D. insularis sp. nov., D. genargenteus sp. nov. and D. ichnusae sp. nov. Besides, two new subspecies are recognized within D. ichnusae (subsp. ichnusae and subsp. toddei). This taxonomical treatment is supported by a multivariate analysis based on 25 morphological characters and 1 phenological character. Each of the taxa is described and illustrated. In addition, notes on nomenclature, ecology, chorology, taxonomical relationships and conservation status are given. Lectotypes are designated for those taxa that are based on material from the investigated territories.