Аннотация:Currently, study of opisthobranch molluscs (including well-known nudibranchs)
are among the most dynamically developed fields of marine biology. Great diversity, intricate evolutionary history and numerous biological peculiarities are features of this remarkable group of the phylum Mollusca. Despite general advancements, currently there is a great deficiency in works on taxonomy of regional opisthobranch faunas. Opisthobranchs of Vietnam are among world’s least studied faunas. Prior to present study, there has been a single review that dealt only with the nudibranch molluscs [Risbec, 1956], and now it is much outdated. Therefore, the review of Vietnam opisthobranch molluscs’ fauna in this study is presented for the first time. For each species short synonymy, diagnostic features and data on its biology and distribution are provided. Every species in this review is illustrated with an original color photograph. In total, 150 species of opisthobranch molluscs have been recorded. This includes most orders: Cephalaspidea, Anaspidea, Umbraculida, Sacoglossa, Notaspidea, Doridacea and Nudibranchia. One of the most important results of this study is 116 species of opisthobranch molluscs that have been recorded for the first time for Vietnamese fauna. A new colorful species, Janolus savinkini sp. nov. is described