Objective: The purpose of this study was to investigate the overlap between executive functions and temperament as measured by two questionnaires and to examine characteristic profiles in children with ADHD and clinical controls. Method: Parents of 111 clinically referred children, half of whom were diagnosed with ADHD and half with other or no diagnoses, completed the Behavior Rating Inventory of Executive Function (BRIEF) and the Cloninger Junior Temperament and Character Inventory (JTCI). Results: Factor analysis of both instruments resulted in three common factors representing aspects of (1) cognitive regulation, (2) behavioral regulation, and (3) anxious/rigid tendencies. Factor (4) represented strengths and positive resources and loaded on JTCI scales only. Both instruments discriminated significantly between ADHD and non-ADHD children. Conduct disorder/oppositional defiant disorder (CD/ODD) but not ADHD accounted for problems in BRIEF Emotional Control and Self-Monitor and JTCI low Cooperativeness. Conclusion: The two instruments only partially overlap and may complement each other.