Achatinella is a tropical genus of colorful land snails in the monotypic Achatinellidae subfamily Achatinellinae. Species are arboreal pulmonate gastropod mollusks with some species called Oʻahu tree snails or kāhuli in the Hawaiian language. Achatinella species are all endemic to the island of Oahu in Hawaii, and all remaining species are endangered. They were once abundant and were mentioned extensively in Hawaiian folklore and songs, and their shells were used in lei and other ornaments.