Problem gambling or ludomania is repetitive gambling behavior despite harm and negative consequences. Problem gambling may be diagnosed as a mental disorder according to DSM-5 if certain diagnostic criteria are met. Pathological gambling is a common disorder associated with social and family costs.

The DSM-5 has re-classified the condition as an addictive disorder, with those affected exhibiting many similarities to those with substance addictions. The term gambling addiction has long been used in the recovery movement. Pathological gambling was long considered by the American Psychiatric Association to be an impulse-control disorder rather than an addiction. However, data suggest a closer relationship between pathological gambling and substance use disorders than exists between PG and obsessive–compulsive disorder, mainly because the behaviors in problem gambling and most primary substance use disorders (i.e., those not resulting from a desire to "self-medicate" for another condition such as depression) seek to activate the brain's reward mechanisms while the behaviors characterizing obsessive-compulsive disorder are prompted by overactive and misplaced signals from the brain's fear mechanisms.

Problem gambling is an addictive behavior with a high comorbidity with alcohol problems. A common tendency shared by people who have a gambling addiction is impulsivity.