Lottery online is an internet-based system in which participants purchase tickets for a chance to win a prize. The prize is usually a cash sum, but can also be an item or service. Lottery online games are played via computers, smart phones, or other devices connected to the Internet. Players can play multiple games at once, or participate in single-game events. The prizes for these games vary by jurisdiction.

In the United States, lottery games are regulated at a state level. Most states have their own lottery games, and some have a single game that is available throughout the state. The state governments oversee these games and their distributions, and many also fund public education systems using lottery proceeds. In addition to traditional state lotteries, private companies operate internet-based games. These sites are sometimes referred to as multi-player, instant or scratch-off lotteries.

Lotteries are popular with people around the world, and are one of the largest sources of revenue for state, provincial, and municipal governments. They are also used to promote tourism and sports events, as well as to provide charitable grants and donations. In some cases, lottery games have been adapted to meet special needs, such as social services.

While the first lotteries were organized in medieval times, modern ones have become a major source of revenue for governments. They are often governed by laws that govern fairness, transparency and security. They may be operated by the state or a private company, and they can be open to the general public or restricted to specific groups, such as senior citizens. Some have been reshaped to meet new needs, such as the advent of electronic communication and the development of instant tickets.

In Canada, there are four nationwide lotteries: Lotto 6/49, Lotto Max (which replaced Lotto Super 7 in September 2009), Daily Grand, and Millionaire Life. These are administered by the Interprovincial Lottery Corporation, a consortium of five regional lotteries owned by their respective provincial and territorial governments: Atlantic Lottery Corporation (New Brunswick, Nova Scotia, Prince Edward Island, Newfoundland and Labrador), Ontario Lottery and Gaming Corporation (Ontario), Loto-Quebec (Quebec), and Western Canada Lottery Corporation (Manitoba, Saskatchewan, Alberta, Yukon, Northwest Territories, Nunavut).

Lotteries are not considered gambling under Lao law, but they are illegal in some regions. The emergence of the internet has enabled many private businesses to offer lotteries online, with some charging premiums on base lottery prices. This has led to the proliferation of lottery-style games that are not officially licensed, and have spawned a number of lawsuits. In the United States, federal courts have ruled that these games violate anti-monopoly laws.