Objective: One suspected source of negative outcomes associated with ADHD has been deficits in executive functions. Although both psychometrically defined and self-reported executive function deficits (EFDs) have been shown to be associated with poor academic and occupational outcomes, whether these two approaches define the same individuals remains unknown. Method: Participants were 194 adults with ADHD from a case-control study of ADHD. Empirically based cutoffs were ascertained for an EFD diagnosis on both psychometric tests and scores on the Current Behavior Scale. Results: Results showed a modest overlap between the psychometric and self-reported definitions of EFDs. Whereas neuropsychological testing largely identified individuals with lower IQ and achievement testing, the behavioral questionnaire largely identified individuals with higher levels of ADHD symptoms, psychiatric comorbidity, and interpersonal deficits. Conclusion: Results indicate that behavioral questionnaires cannot be used interchangeably with neuropsychological testing for the assessment of EFDs in adults with ADHD. (Contains 2 tables and 3 figures.)