Aim: Moyamoya vasculopathy is characterized by progressive stenosis of the major arteries of the Circle of Willis, resulting in compromised cerebral blood flow and increased risk of stroke. The objectives of the current study were to examine intellectual and executive functioning of children with moyamoya and to evaluate the impact of moyamoya type, stroke (clinical or silent), vasculopathy laterality, and disease duration on neurocognitive abilities. Method: Thirty pediatric participants (mean age 10y 10mo, SD 4y; 18 females, 12 males) completed age-appropriate Wechsler Intelligence Scales before any therapeutic revascularization procedures. Reports of executive function were obtained from parents and teachers using the Behavior Rating Index of Executive Function. Results: Children with moyamoya scored significantly lower than the test standardization samples on all indices of intelligence and ratings of executive functioning (p less than 0.001). Patients did not differ by type of moyamoya or history of stroke. Patients with bilateral disease and stroke scored significantly lower than those with unilateral disease on measures of overall intellectual function (p = 0.035) and verbal comprehension (p = 0.04). Deficits in metacognitive executive functions were also more pronounced in bilateral patients according to teacher ratings. Interpretation: Children with moyamoya are at risk for intellectual and executive problems, exacerbated by bilateral disease and clinical stroke history.