Phliantidae is a family of isopod-like amphipod crustaceans chiefly from the southern hemisphere.

Members of the family Phliantidae are unusual among the order Amphipoda, because they have dorso-ventrally flattened bodies with a pronounced dorsal keel, rather than being flattened side-to-side.

[1] Because of this, and various other factors, including the square-ended form of the rostrum, they resemble isopods.

[2] Most species are found in the Southern Hemisphere, where they live on algae in the intertidal zone.

[3] Phliantidae was originally proposed by Thomas Roscoe Rede Stebbing in 1899 for a group that also contained the genera currently placed in the family Prophliantidae, while Temnophlias has also been moved from Phliantidae to its own monotypic families.