Gambling addiction, also known as problem gambling or compulsive gambling, is a behavioral disorder in which a person compulsively bets money in games of chance, even when he cannot afford the cost of doing so. A gambling addiction can create major havoc in the life of its sufferers, their families, and even their employees. Those with a gambling addiction may miss work or school in order to gamble, neglect their families, and steal money with which to gamble. Such individuals may also sell valuables to pay gambling debts and may well bankrupt themselves or others in order to continue placing bets.

While many people are able to play bingo, slot machines, or spend a day at the horse races with no problems, for those with a gambling addiction, these diversions are very difficult to control. Their addiction prevents them from being able to make sound decisions about when to stop gambling, when to leave the gambling premises, or when to stop chasing their losses, a turn of phrase used to describe trying to win back lost money by continuing to gamble.

Some gamblers choose to exercise their compulsion in traditional gambling venues, such as casinos, racetracks, and slot and video poker machines at bars. Others may engage in illegal betting with bookmakers in card games. Some may also gamble on online casinos. When a person with a gambling addiction gambles through illegal channels, she brings additional risks upon herself and her family members, though these risks are generally not enough to compel the gambling addict to stop gambling or seek appropriate treatment.

For many with a gambling addiction, relief can be found in seeking addiction treatment. This may include psychotherapy, particularly cognitive behavioral therapy or the 12-step approach of Gamblers Anonymous (GA). Like most addicts who participate in 12-step programs, a compulsive gambler who chooses to recover from gambling will be expected to cease all forms of gambling and games of chance. Those who choose psychotherapy may modify their behavior in other ways.

Many communities support outreach to problem gamblers, particularly in areas where gambling is legal. Race tracks and casinos often distribute brochures to problem gamblers that provide them with phone numbers of organizations that can assist them with finding appropriate treatment for their condition. In some jurisdictions, gambling addicts can request that they be added to a list of "banne gamblers maintained by casino security agencies so that they are no longer permitted to enter casinos and place wagers.