Background: This article intends to verify the association of dysfunctional beliefs of personality disorders with the executive performance in people with juvenile myoclonic epilepsy (JME). Methods: Fifty-two patients (35 women, 67.3%) with JME aged 18-50 yrs. (32.3 ± 9.7) were evaluated between May 2017 and April 2018 and compared with controls. All subjects were submitted to the Personality Beliefs Questionnaire (PBQ) (Beck & Beck, 1991;Savoia et al., 2006), Dysexecutive Questionnaire (DQ; Wilson et al., 1996;Macuglia et al., 2016), estimated intelligence quotient (IQ) using Vocabulary and Block Design tests, attention and executive functions evaluation (Controlled Oral Word Association (COWA), Digit Span, Trail Making Tests (TMT) A and B, Stroop and Wisconsin Card Sorting Test (WCST)). The inclusion criteria were as follows: diagnosis of JME (ILAE, 1989); age ≥18 yrs., schooling ≥ 11 yrs. and IQ ≥70. The inclusion criteria for the control group were the same except diagnosis of epilepsy. Results: Compared with controls, patients presented higher scores in PBQ for personality disorders, namely Narcissistic (z = −0.79; p b 0.001), Borderline (z = −0.58; p = 0.002), Paranoid (z = −0.43; p = 0.017), and Histrionic (z = −0.39; p = 0.041). Executive functions were impaired when compared with controls in TMT A (z = −0.97; p = 0.038), TMT B (z = −0.65; p = 0.023), and COWA (z = −0.51; p = 0.001). Patients showed higher WCST scores for Errors (z = −1.