A revision of the taxa belonging to the Genista ephedroides group (Fabaceae, Cytiseae) occurring in the Tyrrhenian area is presented. The study, carried out on the basis of the literature, herbarium material, and field and karyological investigations, allows the recognition of 13 taxa. Eight are already known: G. cilentina Vals., G. demarcoi Brullo, Scelsi & Siracusa, G. dorycnifolia Font Quer, G. ephedroides DC., G. gasparrinii (Guss.) C. Presl, G. numidica Spach, G. tyrrhena Vals., and G. valsecchiae Brullo & De Marco, and five are new to science. Genista bocchierii Bacch., Brullo & Feoli Chiapella, G. insularis Bacch., Brullo & Feoli Chiapella, G. insularis subsp. fodinae Bacch., Brullo & Feoli Chiapella, and G. ovina Bacch., Brullo & Feoli Chiapella are described from Sardinia, Italy, while G. tyrrhena subsp. pontiana Brullo & De Marco is described from the Pontine Archipelago of Latium, Italy. Karyologically, most of the taxa are characterized by the somatic number 2n = 48 (G. bocchierii, G. cilentina, G. demarcoi, G. dorycnifolia, G. gasparrinii, G. tyrrhena subsp. tyrrhena, G. ephedroides, G. valsecchiae, G. insularis), with accessory chromosomes occasionally yielding higher counts. In addition to 2n = 48, the new report of 2n = 44 is noted for the new species G. ovina. A new count of 2n = 48 is reported for G. tyrrhena subsp. tyrrhena, whereas higher counts (2n = 48 0–2B, 72, 96) are reported for the new subspecies G. tyrrhena subsp. pontiana. For each examined taxon, notes are given on the nomenclature, karyology, ecology, and chorology, while a detailed iconography is lacking only for G. numidica and G. dorycnifolia. An analytical key for the G. ephedroides group is presented. Lectotypes are designated for G. numidica and Spartium gymnopterum Viv.