A young girl with L-dopa responsive dystonia showed significant improvements in motor function but had ongoing complaints of neuropsychological difficulties. A neuropsychological evaluation was undertaken to understand the nature of her difficulties. Intellectual function, attention, executive function, and academic attainment were assessed using published psychometric tests. Verbal and non-verbal reasoning was found to be age appropriate. Particular difficulties were identified with working memory, visual selective attention, dual attention, and processing speed which were having a significant impact upon the child and her family. The importance of a thorough neuropsychological evaluation is discussed in helping to appropriately manage and support the child with this chronic but rare health condition.