The lottery is a form of gambling in which participants pay to buy a ticket and hope to win a prize by matching numbers or symbols on the ticket to those randomly drawn by a machine. It is a form of gaming that has a long history and widespread acceptance in many countries. The prize money may be cash or goods. In the latter case, the amount of money a participant can win depends on the number and value of tickets sold.

Lotteries have been around since ancient times, with a practice of distribution by lot being one of the most basic forms of human governance. The practice was also widely used in medieval Europe, with towns using it to raise funds for fortifications and other town projects and for the poor. The first European public lotteries were organized by Francis I of France, who had been inspired by his visits to Italy and wished to help state finances.

Generally, state lotteries legislate a monopoly for themselves; establish a state agency or public corporation to run the lottery (as opposed to licensing a private firm in return for a portion of the profits); begin operations with a modest number of relatively simple games; and, driven by the constant pressure for additional revenues, progressively expand their offerings. This expansion, however, often leads to a point of diminishing returns.

This ongoing evolution of state lotteries is often at cross-purposes with the public interest. The promotional focus on winning large sums is at odds with concerns about problem gamblers, the regressive impact of the lottery on lower income groups, and other issues of public policy.