Allium croaticum, a new species from the island of Vis in Central Dalmatia (Croatia) is described and illustrated. Its relationships with allied species belonging to the A. stamineum group (Allium section Codonoprasum) are discussed. It is a diploid species (2n = 16), colonizing calcareous screes and flowering in early summer. Its morphology, leaf anatomy, karyology, palynology, ecology and taxonomic position are examined. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 106–114.