The distribution of the genus Tandonia includes Europe to North Africa and Asia Minor.

[2] The slug's body is elongate, up to 100 mm in length, and usually with almost parallel sides.

The posterior par is abruptly narrowed, the keel usually low and is restricted to the last section of the dorsum in some species, reaching the mantle margin in others.

The vas deferens of specific length opens into the posterior end of the epiphallus.

[2] Within the genus Tandonia there are the following 29 species:[3] This article incorporates public domain text from the reference.