Gammaridea is one of the suborders of the order Amphipoda, comprising small, shrimp-like crustaceans.

Until recently, in a traditional classification, it encompassed about 7,275 (92%) of the 7,900 species of amphipods described by then, in approximately 1,000 genera, divided among around 125 families.

The group is however considered paraphyletic, and is under deconstruction by the amphipod taxonomists James K. Lowry and Alan A. Myers.

In 2003 they moved several families from Gammaridea to join members of the former Caprellidea in a new suborder Corophiidea.

[2] Further, in 2013 another large suborder Senticaudata was established, which now encompasses much of the original Gammaridea, particularly its freshwater families, and into which also the Corophiidea was merged.