Online Gambling refers to the use of a computer or device to place wagers on games of chance. Various games can be played in this manner, including sports betting and online lottery tickets. Some states have legalized online gambling while others have prohibited it. Many online casinos offer time-out periods, where the player voluntarily locks themselves out of their account for a set period of time. Some of these services also allow players to set loss limits, ensuring that their bankroll does not deplete too quickly.

There are concerns that Internet gambling may contribute to the development of gambling problems. Compared with offline gambling, the ability for individuals to make large wagers, engage in continuous gambling and rapidly obtain feedback from their own behaviour is thought to increase the potential for problematic behaviours. In addition, it is possible that the increased accessibility of Internet gambling may encourage more people to gamble, irrespective of their existing gambling involvement. These factors have led to the inclusion of a new category of Non-Substance Behavioural Addiction in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).

While online gambling is generally legal in most EU countries, it is illegal for banks to process transactions that are intended to fund such activities in a country where this is illegal. This is because of the dormant Commerce Clause doctrine, which states that federal law preempts state laws in regards to regulating gambling activities outside their borders.