Anostoma, common name the up-mouth snails, is a genus of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Tomogeridae.

Snails in this genus are found in Brazil.

Adult snails in this genus have an extremely unusual shell morphology: the aperture of the adult shell faces directly "upwards", in other words, in the same direction as the spire. This seemingly impossible arrangement is made possible because the adult shell is carried upside down.

In 1901, the American malacologist Henry Augustus Pilsbry commented that the adult shell of Anostoma is "so bizarre that in the total absence of information upon its life history, no useful theory can be formulated to account for its peculiarities."

A very similar shell is found in the genus Ringicella Gray, 1847, which was previously considered to be merely a subgenus within Anostoma.

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