A lottery is a form of gambling in which numbers are drawn at random for prizes. Some governments outlaw it, while others endorse it to the extent of organizing state or national lotteries. Lottery games are often regulated, and many have specific rules designed to discourage cheating. For example, some states prohibit the use of a computer to determine winners or to record the results of previous draws.

Although the casting of lots has a long history (including several instances in the Bible), the modern lottery is comparatively recent. It was introduced in the United States in the immediate post-World War II period as a way for states to raise funds without burdening middle class and working people with higher taxes. Its popularity in this period was fueled by growing economic inequality and by a newfound materialism that claimed anyone could become rich with enough effort or luck.

Lottery advertising necessarily focuses on convincing target groups to spend their money on the game, and that focus may not always align with the larger public interest. For instance, studies have shown that lottery play tends to decline with education, and that lower-income people gamble more heavily relative to their incomes.

Lottery revenues are primarily used for government programs and services, but some states also dedicate them to private projects and charities. Generally, a percentage of ticket sales goes toward administrative and vendor costs; the remainder is awarded to prize winners.