Chapter 20 of Addiction Medicine outlines the impact of and management approaches for gambling disorders. Gambling, defined as betting something of value on an event which cannot be correctly predicted, is a near-universal human activity, but for a minority of people it can develop into a major disorder. The prevalence and types of gambling worldwide are outlined, and the impact of electronic forms is emphasized, noting that slot machine gambling and internet betting have become dominant in many societies. The behavioural and personal impacts of gambling disorders are outlined. Gambling disorders are now accepted as addictions in the international diagnostic and classification systems. Psychiatric and social antecedents and comorbidities are highlighted. Approaches to assessment are described and the non-specificity of symptoms and the hidden nature of gambling in many cases are highlighted. Management principally entails psychological therapies and involvement with self-help fellowships, but pharmacological treatments have a role.