A key to the seven species of the Gammarus locusta-group is given. Four of these have got a new name: G. inaequicauda (= G. campylops Sars non Leach), G. insensibilis (= G. locusta Della Valle non Linnaeus), G. crinicornis (= G. plumicornis Pirlot non Costa) and G. subtypicus (= “Gammarus locusta forme subtypique”, of Rancurel).