Helicids occur on Cape Verde[2] (Eremina), Canary Islands (Theba, Hemicycla) and the Madeira Archipelago (Lampadia, Idiomela).

[8] Some species, notably Cornu aspersum and Theba pisana have been introduced and become established in numerous different areas worldwide.

The family Helicidae contains 3 subfamilies (according to molecular phylogenetic analyses[9][10][11][12]): Genital system anatomy (does not apply on all species, as derived states are found in some of them): mucous glands divided into 2 or more branches, love dart with four blades (vanes) along its length, two penial papillae/verges.

[14] Genital system anatomy (does not apply on all species, as derived states are found in some of them): mucous glands weakly branched or undivided, love dart with four blades along its length, one penial papilla.

[15][16] Genital system anatomy: mucous glands divided into 2 branches or undivided, love dart with two blades on the tip, one penial papilla.