Gambling is risking something of value on an activity that relies on chance in the hopes of realizing a profit. It has existed in virtually every society since prerecorded history, and is incorporated into local customs and rites of passage through the ages. Although most people who gamble do not become addicted, a small percentage overindulge and incur debts that impair their ability to support themselves and others.

The most common form of gambling is placing a bet on a sporting event, but it can also be found in the stock market and lottery games. In the United States, there are many different types of gambling, and the laws that govern them vary greatly from state to state. Some forms of gambling are illegal, and violators may face fines or jail time. Some types of gambling are also considered to be a type of business, and those who operate a casino or other gambling establishment can be subject to regulations.

While there are differences between the psychological processes that occur in different gambling activities, clinical and neurobiological research has categorized them all into one category based on their consistent phenomenology. Regardless of the specific game or setting, all gambling involves the same basic sequence: A person chooses what they want to bet on, such as a football team or scratchcard, and then matches their selection with the odds of that event happening, which are often set by the betting company or published in the media.