Lophogastrida is an order of malacostracan crustaceans in the superorder Peracarida, comprising shrimp-like animals that mostly inhabit the relatively deep pelagic waters of the oceans throughout the world.
Most lophogastridan species are long, but Gnathophausia ingens can be up to , probably the largest pelagic crustacean in the world.
Previously, Lophogastrida was classified as a suborder of a broader peracaridan order, Mysidacea, together with Mysida and Stygiomysida, but that taxon has been generally abandoned. Features distinguishing lophogastrids from the mysids include the absence of statocysts in their uropods, and the presence of well-developed biramous pleopods on their abdomens.