The genus Leptobium Casey, 1905 (Coleoptera: Staphylinidae: Paederinae) is represented in the Palearctic Region by 73 species and two subspecies. As a result of field survey in the north and southern Turkey between 2008 and 2021, a new species of the genus Leptobium is described and illustrated from Tekirdağ Province (Ganos Mountains, northwestern Turkey), and distinguished from related congeners: Leptobium thracicum sp. n. Additional records of five species of Leptobium from Turkey are presented. The genus is now represented in Turkey by 20 species with 15 of them endemic.