Shoplifting is the theft of goods from an open retail establishment, typically by concealing a store item on one's person, in pockets, under clothes or in a bag, and leaving the store without paying. With clothing, shoplifters may put on items from the store and leave the store wearing the clothes. The terms shoplifting and shoplifter are not usually defined in law. The crime of shoplifting generally falls under the legal classification of larceny. Shoplifting is distinct from burglary (theft by breaking into a closed store), robbery (stealing by threatening or engaging in violent behavior), or armed robbery (stealing by using a weapon). In the retail industry, the word shrinkage (or shrink) can be used to refer to merchandise lost by shoplifting, but the word also includes loss by other means, such as waste, uninsured damage to products and theft by store employees.

Shoplifters range from amateurs acting on impulse, to career criminals who habitually engage in shoplifting as a form of income. Career criminals may use several individuals to shoplift, with some participants distracting store employees while another participant steals items. Amateurs typically steal products for personal use, while career criminals generally steal items to resell them in the underground economy. Other forms of shoplifting include swapping price labels of different items, return fraud, or eating a grocery store's food without paying for it. Commonly shoplifted items are those with a high price in proportion to their size, such as disposable razor blades, vitamins, alcoholic beverages, and cigarettes.

Stores use a number of strategies to reduce shoplifting, including storing small, expensive items in locked glass cases; chaining or otherwise attaching items (particularly expensive ones) to shelves or clothes racks; attaching magnetic or radio sensors or dyepacks to items; installing curved mirrors mounted above shelves or video cameras and video monitors, hiring plainclothes store detectives and security guards, and banning the bringing in of backpacks or other bags. Some stores have security guards at the exit, who search backpacks and bags and check receipts. Stores also combat shoplifting by training employees how to detect potential shoplifters.

The first documented shoplifting started to take place in 16th century London. By the early 19th century, shoplifting was believed to be primarily a female activity. In the 1960s, shoplifting began to be redefined again, this time as a political act. Researchers divide shoplifters into two categories: boosters (professionals who resell what they steal), and snitches (amateurs who steal for their personal use).