BACKGROUND Suicidal behaviours are prevalent in substance use disorder (SUD) patients. These behaviours have a negative impact on the psychopathological profile of these patients. However, few studies have evaluated suicide as a continuum (i.e. starting with ideation, followed by attempts and ending with death) and its evolution during treatment. The aim of this scoping review was to explore what is known about suicidal behaviour in individuals undergoing clinical treatment for SUD. METHODS The PsycINFO, Web of Science (Core Collection and MEDLINE), Scopus, and Cochrane Library databases were searched. After screening the records based on eligibility and exclusion criteria, 30 studies were ultimately selected for inclusion. RESULTS Most of the studies were conducted in the USA and Europe. Only three studies evaluated suicidal behaviour with a specific instrument. The prevalence of suicidal ideation (SI) in people being treated for SUD ranged from 20 % to 62.2 %, and the prevalence of suicide attempts (SA) ranged from 15.8 % to 52.1 %. Only one study reported death by suicide. CONCLUSIONS Despite the high prevalence of suicidal behaviours and their harmful consequences, the assessment of this phenomenon is scarce and heterogeneous. There is a need to assess suicidal behaviour with standardized criteria in order to develop tailored SUD treatment.