Abstract Introduction As legalization of cannabis products continues, cannabis use becomes more prevalent, and concerns regarding cannabis use disorder (CUD) rise, improving CUD treatment has become increasingly important. Techniques used to regulate emotions, such as cognitive reappraisal, may help manage cravings for cannabis in individuals with CUD. Transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique, may improve regulation of emotions and reduce substance use. This study aims to determine whether the addition of tDCS to training in cognitive reappraisal leads to greater reductions in cravings and cannabis use than cognitive reappraisal without active stimulation. Methods and analysis This longitudinal between-subjects study will...