The species belonging to the genus Crangon Fabricius, 1798 only occur in the Northern Hemisphere both in Atlantic and Pacific waters. The higher number of species of Crangon in the Pacific suggests that they originated from this area. To date, a few studies have identified some common features between members of the genus, but the species have largely been ignored in taxonomic, phylogeographic, and ecological research efforts. Crangon are all carnivores or omnivores probably with a relevant ecological role; in some cases top-down control by the type species, C. crangon (Linnaeus, 1758), has been suggested. Several species live in shallow coastal waters and might represent abundant prey for fish including flatfish during their nursery period; the shrimp themselves prey upon the early life stages of flatfish. Because of their high abundance, some shrimp have commercial value not only for human consumption but also as bait. However, the taxonomic status within Crangon and genetic relationships among populations within species are still unsettled. Also, their geographic ranges and general life cycle features are poorly documented. Despite occurring only in the Northern Hemisphere, Crangon are originally temperate water species. Most have still a high upper tolerance limit but are also quite adapted to low temperatures. They might then have a high temperature tolerance range which will be beneficial in a climate change scenario. In this work we review previous investigations on the various species of Crangon across the spread of their geographic occurrence and highlight issues requiring further research.