Up to 12% of patients with stroke have intracranial arterial dolichoectasia (IADE) and the basilar artery is affected in 80% of these cases. Diagnostic criteria and prognosis studies of IADE are based on basilar artery diameter, which is a good quantitative marker for the severity of the disease. The pathophysiology is largely unknown, but IADE can be viewed as a common final pathway of arterial wall response or damage in the tunica media due to various mechanisms, such as matrix metalloproteinase dysfunction or muscle cell or elastic fibre injury. No randomised controlled trials have been undertaken in IADE and thus little high-level evidence is available on which to base treatment guidelines. IADE management depends on clinical presentation and disease severity, and includes blood pressure control, antithrombotic treatments, endovascular procedures, and surgery. Further studies are needed to better define IADE in the general population, to establish its prevalence and pathophysiology, to identify subgroups at risk of life-threatening complications, and to offer effective treatment options.