无甲目（学名：Anostraca），亦作无背甲目或无被甲目，是甲壳亚门鳃足纲之下四大目的其中一个目，其成员有神仙虾或仙女虾的别名。在缌足纲里，无甲目是萨甲亚纲之下的唯一一个目。

无甲目是鳃足纲四大目之中最为分化的一个目，包括有约300个物种，可分为八个科26个属：

Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are also known as fairy shrimp. They are usually 6–25 mm (0.24–0.98 in) long (exceptionally up to 170 mm or 6.7 in). Most species have 20 body segments, bearing 11 pairs of leaf-like phyllopodia (swimming legs), and the body lacks a carapace. They live in vernal pools and hypersaline lakes across the world, including pools in deserts, in ice-covered mountain lakes and in Antarctica. They swim "upside-down" and feed by filtering organic particles from the water or by scraping algae from surfaces. They are an important food for many birds and fish, and are cultured and harvested for use as fish food. There are 300 species spread across 8 families.