Few metazoan species are fixed for left-right reversal throughout development. Against this animal rule of homochirality, clockwise-coiled (dextral) and counterclockwise-coiled (sinistral) snails repeatedly evolved by reversal (chiral speciation). In land snails, most genera include only dextral taxa, except for the family Clausiliidae, in which most species are sinistral. The snail fauna of Turkey is exceptionally rich compared with other temperate regions. The centres of diversity of several genera or even families are probably in Turkey, suggesting their longer history of diversification. About 25% of Turkish species are sinistral. They belong to the families Enidae, Orculidae and Clausiliidae. Seven of the 25 enid genera contain sinistral taxa. In at least 6 of them, the dextral and sinistral morphs coexist, where dextrals are as frequent as 0.5 to 50 %. Two of the 6 orculid genera contain sinistral taxa. In the Clausiliidae, one species is dextral while the other taxa remain sinistral. These tall-shelled groups of simultaneous hermaphrodites copulate non-reciprocally. Thus, copulation between the reversed mutant and the wild-type majority would not be so physically difficult as that in simultaneously reciprocally mating groups. These Turkish snails will allow us to verify the history and mechanism of chiral speciation against the animal rule.