Drug, alcohol and tobacco use disorders are a global burden affecting millions of people. Despite decades of research, treatment options are sparse or missing, and relapse rates are high. Glucagon-like peptide 1 (GLP-1) is released in the small intestine, promotes blood glucose homeostasis, slows gastric emptying and reduces appetite. GLP-1 receptor agonists approved for treating Type 2 diabetes mellitus and obesity have received attention as a potential anti-addiction treatment. Studies in rodents and non-human primates have demonstrated a reduction in intake of alcohol and drugs of abuse, and clinical trials have been initiated to investigate whether the preclinical findings can be translated to patients. This review will give an overview of current findings and discuss the possible mechanisms of action. We suggest that effects of GLP-1 in alcohol and substance use disorders is mediated centrally, at least partly through dopamine signalling, but precise mechanisms are still to be uncovered.