Gambling is the wagering of something of value on a random event with awareness of risk in the hope of gaining more. It ranges from the buying of lottery tickets and betting small amounts on sporting events by people who have little, to sophisticated casino gambling for profit or as a pastime. Gambling is a popular activity worldwide that has both negative and positive social and economic impacts on gamblers and their significant others, as well as on society. These impacts are influenced by the degree, duration, and severity of gambling problems.

Gambling has been a common leisure activity for centuries, but it was also suppressed by law in many areas. In the early 20th century, it was almost uniformly illegal and a major source of revenue for the mafia. However, the late 20th century has seen a gradual softening of attitudes and a relaxing of laws regarding gambling. Today, about 20 percent of the American population participates in gambling to some extent.

There are both personal and societal costs and benefits associated with gambling, which can be grouped into three classes: financial, labor, and health and well-being. The financial costs include gambling revenues, tourist expenditures, and changes in the cost or value of infrastructure. The labor impacts include changes in work performance and the impact on employment opportunities, and the health and well-being impacts encompass a wide variety of physical, psychological and social outcomes. Each of these classes can be broken down further to identify specific effects at the personal, interpersonal, and community/societal levels.