Lotteries are government-sponsored games of chance in which participants have a chance to win a prize, often money. Depending on the country, a lottery can be played at the state, provincial, territorial or national level. Lotteries are often used to raise funds for public good projects such as schools, hospitals and infrastructure development. In the United States, large portions of many state lotteries are used for public education systems. Other states use a portion of their lotteries to fund public services such as health and welfare programs.

In addition to the traditional number-drawing game, many modern lotteries have incorporated instant games such as scratch-off tickets and keno into their offerings. Some have also introduced video lottery terminals, which are a type of slot machine. Regardless of their method of operation, all lotteries are subject to gambling laws in the jurisdiction where they operate.

Traditionally, lotteries are regulated by governments at both the local and national levels. For example, the state of New York, which operates a multi-state game called the Mega Millions, regulates its own distribution system as well as oversees the legality of its retail outlets and vendors. The state of Massachusetts has a similar arrangement, with its own licensing and distribution authority. In the US, the most popular instant lotteries are scratch-off tickets, while keno and video lottery terminals (VLTs) have become increasingly common.

While there is a lack of uniformity among lottery regulations across the world, most countries have some form of law on the books that makes it illegal to operate a lottery without a license. In some cases, the license is obtained through a state agency such as the Gaming Control Board. In other cases, the lottery is operated by a private company licensed by the state. In the United Kingdom, there are two state-run lotteries: the National Lottery and Thunderball. In Canada, prior to 1967 it was illegal to buy a lottery ticket, but that year the Liberal government introduced a special bill (an Omnibus Bill) to bring up-to-date a number of obsolete laws.

While the bill was intended to allow Quebecers to participate in the Montreal lottery, it did not include a lottery for the city of Toronto. However, the city was soon able to establish its own public lottery through a private company. The company, known as the Milli Piyango, offered four different games: Cilgin Sayisal Loto (6/90), Super Loto, Sans Topu (5/34 + 1/14), and On Numara. Its success led to other cities establishing their own private lotteries, which are now largely defunct. The Milli Piyango Idaresi was privatised in 2019. In other countries, the lottery is run by the central government, a province or a territory.