The process of allocating something, such as tickets to an event or the proceeds of a game, by chance, rather than by merit or careful organization. The term is often used to describe a situation in which the benefits of monetary gain outweigh the cost, but it can also be applied to non-monetary situations such as obtaining units in a subsidized housing complex or kindergarten placements at a prestigious public school.

Lotteries are run as businesses that aim to maximize revenues by persuading target groups to spend their money on the games. As a result, they are at odds with the social responsibilities of government. Critics point to problems with compulsive gambling, regressive impacts on poorer groups, and other issues of public policy.

Lotteries have been around for centuries and are a common way for governments to raise money. They were once viewed as a painless form of taxation, allowing citizens to voluntarily spend their money in order to benefit the community. The first state lotteries, in the Low Countries in the 15th century, raised money for town fortifications and for helping the poor. Today, people pay for lottery tickets to win prizes such as cars, cash, or houses. Most of the money goes to organizing costs and the remainder is awarded in a random draw. Ticket sales tend to increase for rolling-over jackpot drawings, but the number of larger prizes must be balanced against the cost of promoting and running the lottery.