Based on a phylogenetic analysis of 104 genera and 156 species of corophiidean amphipods, we present a new phylogeny and higher-level classification for the suborder Corophiidea Leach, 1814. The phylogeny divides the corophiideans into two infraorders, the Corophiida and the Caprellida, based on a hypothesis of the evolution of different feeding strategies. Members of the Corophiida are derived from bottom-feeding detritivores, whereas members of the Caprellida are derived from ancestors that fed on material suspended in the water column. Within the Corophiida there are unspecialized clades such as the aoroids, whose members are mainly detrital feeders, as well as specialized forms feeding on living algae (family Ampithoidae) and on wood (superfamily Cheluroidea). In the Caprellida, members of the podocerid and caprellid clades often climb organisms such as hydroids in order to get their antennae as far up in the water column as possible to suspension-feed, whereas ischyrocerins build nests and then suspension-feed. Specialized forms include cyamids that attach to whales where they “feed on whale skin.” Barnard and Karaman (1984) divided the Corophiidea into two superfamilies (Corophiidea and Caprelloidea) within which were nine families. The classification presented here includes those two infraorders, with 11 superfamilies, 21 families, 13 subfamilies, and 5 tribes.