Background: Confirmatory factor analysis (CFA) was used to determine if oppositional defiant behavior (ODB) toward adults and oppositional defiant behavior toward other children were constructs distinct from each other as well as from attention-deficit/hyperactivity disorder-hyperactivity/impulsivity (ADHD-HI), attention-deficit/hyperactivity disorder-inattention (ADHD-IN), and academic competence. Methods: Mothers and fathers rated the occurrence of the DSM-IV oppositional defiant disorder (ODD) symptoms where the target was an adult (e.g., argues with adults) and the ODD symptoms where the target was another child (brothers, sisters, or peers) (e.g., argues with other children) along with ADHD-IN, ADHD-HI, and academic competence in a sample of 894 Brazilian children on the Portuguese version of the Child and Adolescent Disruptive Behavior Inventory (CADBI). Results: The ODB-Adults' and ODB-Children's factors showed invariance (i.e., equality of like item loadings, intercepts, residuals; as well as like factor variances, covariances, and means), convergent validity, and discriminant validity from each other as well as from ADHD-IN, ADHD-HI, and academic competence between mothers' and fathers' ratings. Conclusions: With the Portuguese parent version of the CADBI, the evidence indicated that ODB-Adults and ODB-Children represent two constructs rather than one. The distinction between ODB-Adults and ODB-Children allows for a more specific study of the development of ODB in children.