Objective Experiences from clinical practice suggest that behavioural symptoms in patients with Korsakoff syndrome (KS) are a frequent problem. Knowledge about behavioural symptoms is important in understanding and managing these symptoms. The aim of this study is to review the prevalence and severity of behavioural symptoms in KS. Methods Relevant articles were identified by searching Medline (PubMed), PsycINFO, Embase and CINAHL up to 4 June 2014. Two reviewers independently selected the studies, extracted their baseline data and assessed methodological quality using a standardized checklist. Results Fifteen studies fulfilled the inclusion criteria. A diversity of diagnoses was used indicating that KS and other alcohol‐related cognitive disorders and terms were used interchangeably. None of the studies were primarily designed to estimate the prevalence or severity of behavioural symptoms in patients with KS. Most studies had serious methodological limitations. The reported prevalence estimates of behavioural symptoms in the included studies varied strongly. Most prevalent were depressive symptoms and disorders (2–50%, median 27%) and agitation and aggression (10–54%, median 27%). None of the reported, mean severity estimates met pathological thresholds. The highest severity estimates were found for apathy. Conclusions Good quality studies on behavioural symptoms in patients with KS are lacking. Observational research designed to provide reliable estimates of the prevalence and severity of behavioural symptoms in patients with KS is needed. This could improve understanding and managing these symptoms and help care staff to better support the needs of this specific patient group. Copyright © 2016 John Wiley & Sons, Ltd.