Moyamoya disease is a cerebrovascular condition characterized by progressive occlusion of the cerebral vessels, particularly in the circle of Willis. This report describes the case of a 12-year-old boy presenting with a history of recurrent right-sided weakness over a period of seven years. Magnetic resonance imaging revealed evidence of both old and recent infarcts, as well as encephalomalacic changes. The diagnosis was confirmed by magnetic resonance angiography, which demonstrated severe stenosis in both internal carotid arteries and the presence of significant collateral formation. In Bangladesh, surgical revascularization for Moyamoya disease had not been previously attempted, and due to financial constraints, the patient’s family opted for conservative management with anti-platelet therapy and regular follow-ups. Although a hereditary component is often presumed in Moyamoya disease, no such familial history was identified in this case. Additionally, no associations with immunological, infectious, hematological, vascular, or congenital syndromes were found. Mortality rates for Moyamoya disease are approximately 10% in adults and 4.3% in children, with a significant proportion of affected individuals experiencing cognitive decline. However, the patient in this case maintained intact cognitive function, and with diligent follow-up and anticoagulation therapy, it was anticipated that his functional capacity would remain stable.