Objective The aim of this study was to examine expressive language, memory, and higher executive tasks in patients with juvenile myoclonic epilepsy (JME) as compared with their siblings and a normal control group under video-EEG conditions. Methods Eight sibling pairs, one in each pair with JME, were compared with 16 controls matched for age, sex, ethnicity, and educational level. The participants were administered a standard comprehensive set of neuropsychological measures to assess emotional well-being, intelligence, memory, language, visuospatial skills, reaction time, attention, and higher executive function, during and without video-EEG recording. Results The JME group differed significantly from controls on measures of phonemic and semantic verbal fluency. They also scored significantly higher on the Dysexecutive Questionnaire, being much more likely to report traits associated with executive dysfunction. Qualitative inspection of the data suggested a trend for patients with JME and their siblings to perform worse than controls on some measures, notably those of expressive language and higher executive function, but on other measures the differences were not statistically significant. In contrast, the JME and sibling group performed as well as controls on the Rey Complex Figure and other tests of visuospatial skills. Conclusion The present controlled experimental case series provides support for a neuropsychological profile of patients with JME and their siblings. Significant impairments in verbal and executive functioning may have important ramifications for the social, occupational, and academic performance of people with JME. The apparent corresponding likeness in cognitive performance, exhibited independent of EEG activity, between patients with JME and their siblings warrants further exploration as similar cortical and subcortical structures may be implicated in these two groups.