Shrimp are swimming decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important food source for larger animals from fish to whales. They have a high resistance to toxins in polluted areas, and may contribute to high toxin levels in their predators. Together with prawns, shrimp are widely caught and farmed for human consumption.

Most shrimp mature and breed only in a marine habitat, although there are a small number of freshwater species. The females lay 50,000 to 1 million eggs, which hatch after some 24 hours into tiny nauplii. These nauplii feed on yolk reserves within their body and then undergo a metamorphosis into zoeae. This second larval stage feeds in the wild on algae and after a few days metamorphoses again into the third stage to become myses. At this stage the myses already begin to appear like tiny versions of fully-developed adults and feed on algae and zooplankton. After another three to four days they metamorphose a final time into postlarvae: young shrimp having all the characteristics of adults. The whole process takes about 12 days from hatching. In the wild, the marine postlarvae then migrate into estuaries, which are rich in nutrients and low in salinity. There they grow and eventually migrate back into open waters when they mature. Most adult shrimp are benthic animals living primarily on the sea floor.

While in biological terms shrimps and prawns belong to different suborders of Decapoda, they are very similar in appearance. In commercial farming and fisheries, the terms shrimp and prawn are often used interchangeably. However, recent aquaculture literature increasingly uses the term prawn only for the freshwater forms of palaemonids and shrimp for the marine penaeids.

In the United Kingdom, the word prawn is more common on menus than shrimp, while the opposite is the case in North America. The term prawn is also loosely used to describe any large shrimp, especially those that come 15 (or fewer) to the pound (such as king prawns, yet sometimes known as jumbo shrimp). Australia and other Commonwealth nations follow this British usage to an even greater extent, using the word prawn almost exclusively.

In Britain very small crustaceans with a brownish shell are called shrimp, and are used to make potted shrimp. They are also used in dishes where they aren't the primary ingredient

As with other seafood, shrimp is high in calcium, iodine and protein but low in food energy. A shrimp-based meal is also a significant source of cholesterol, from 122mg to 251mg per 100g of shrimp, depending on the method of preparation. Shrimp consumption, however, is considered healthy for the circulatory system because the lack of significant levels of saturated fat in shrimp means that the high cholesterol content in shrimp actually improves the ratio of LDL to HDL cholesterol and lowers triglycerides.

Shrimp and other shellfish are among the most common food allergens. They are not kosher and thus are forbidden in Jewish cuisine. However, according to some mazhab, shrimp are halal, and therefore are permissible in Islamic cuisine.