Bythinella, a highly diverse rissooidean genus, has a wide distribution area from the Iberian Peninsula to Asia Minor. More recent research about this genus revealed many taxa especially in the Balkan region. However, very few records were known from Turkey. This study aimed to describe a new species: Bythinella kazdaghensis sp. n. from the Mount Ida (Kaz Dagi) in Northwestern Turkey. Bythinella kazdaghensis sp. n. was compared with the species of Turkey and Greece as well. This new species was found to be similar to B. turca (Radoman, 1976) in terms of shell height.