We describe Andvakia discipulorum Daly & Goodwill, n. sp., from an intertidal mudflat of Kāne‘ohe Bay, O‘ahu, Hawai‘i. Members of this species are inconspicuous, being small and having a column covered with sand. In comparison with other species of the genus, Andvakia discipulorum, n. sp., presents distinct arrangement of mesenteries, sizes of nematocysts, and musculature. We also provide a redescription of Andvakia boninensis based on specimens collected from Saipan, Mariana Islands. These descriptions provide an opportunity to revise and update the taxonomy of Andvakia and to address the systematics of family Andvakiidae. We determine that Andvakia is the senior synonym of Decaphellia and reject earlier hypotheses of synonymy between Andvakia and Capneopsis, Ilyactis, and Octophellia. A tabular key to the species of Andvakia is provided.