Lottery is a form of gambling in which participants pay for the chance to win a prize, which can range from money to goods and services. Federal laws prohibit the mailing or transportation in interstate or foreign commerce of lottery promotions or tickets themselves, and most states have passed laws regulating the conduct of state-sponsored lotteries. The term lottery is also used to describe a system of selecting people or groups to participate in a government-sponsored event, such as the selection of draft conscripts for the Vietnam War.

The casting of lots to determine fates or to distribute goods has a long history in human culture, including several instances in the Bible. However, the modern use of lotteries as a source of funds has only recently come into vogue. The first recorded public lotteries to offer tickets and prizes of unequal value were held in the Low Countries in the 15th century, with records of lottery-like arrangements found in the towns of Ghent, Utrecht, and Bruges.

The popularity of lotteries varies by state, but they tend to win wide public support when the proceeds are perceived to be a painless form of taxation and the government is facing fiscal challenges. But studies have shown that the overall success of a lottery cannot be based solely on its ability to raise and retain this kind of public support; it must also be able to manage its operations effectively, with attention to the concerns about compulsive gambling and its alleged regressive impact on lower-income groups.