A lottery is a game in which prizes are allocated through a process that relies on chance. People pay for a ticket or tickets and then select numbers, either manually or by using machines that randomly spit out numbers. They win a prize if enough of their numbers match those selected by the machine.

Most states and the District of Columbia operate state-sponsored lotteries. In addition to traditional scratch-off games, most now offer a range of other gambling products, including instant-win games, daily games, and games that ask players to select three or four numbers. A growing number of cities and private companies also run lotteries.

The earliest lottery records date back to the Low Countries in the 15th century, when towns used them to raise funds for town walls and fortifications. By the 17th century, some states had established a lottery system to help the poor.

In modern times, the lottery has become a major source of state revenue, with governments promoting it as an attractive alternative to raising taxes. Critics, however, argue that while lotteries may provide some benefits to the general population, they have a significant impact on the poor and on problem gamblers; promote addictive gambling behavior; serve as a regressive tax on lower-income groups; and put the government at cross-purposes with its responsibility to protect the public welfare.

The majority of lottery participants are in the middle to bottom quintiles of income. They tend to spend a greater proportion of their discretionary income on lottery tickets than do those in the upper quintiles. The very poor, on the other hand, do not participate in lotteries at any appreciable level, because they simply do not have the disposable income to do so.